diff --git a/api/src/main/kotlin/io/smnp/data/entity/Note.kt b/api/src/main/kotlin/io/smnp/data/entity/Note.kt
index 0b94e52..a913684 100644
--- a/api/src/main/kotlin/io/smnp/data/entity/Note.kt
+++ b/api/src/main/kotlin/io/smnp/data/entity/Note.kt
@@ -1,26 +1,38 @@
 package io.smnp.data.entity
 
 import io.smnp.data.enumeration.Pitch
+import io.smnp.math.Fraction
 
-data class Note(val pitch: Pitch, val octave: Int, val duration: Int, val dot: Boolean) {
-   data class Builder(
-      var pitch: Pitch = Pitch.A,
-      var octave: Int = 4,
-      var duration: Int = 4,
-      var dot: Boolean = false
-   ) {
-      fun pitch(pitch: Pitch) = apply { this.pitch = pitch }
-      fun octave(octave: Int) = apply { this.octave = octave }
-      fun duration(duration: Int) = apply { this.duration = duration }
-      fun dot(dot: Boolean) = apply { this.dot = dot }
-      fun build() = Note(pitch, octave, duration, dot)
-   }
+class Note(val pitch: Pitch, val octave: Int, duration: Fraction, dot: Boolean) {
+   val duration = if(dot) duration * Fraction(3, 2) else duration
+
+   operator fun plus(duration2: Fraction) = Note(pitch, octave, duration + duration2, false)
 
    override fun toString(): String {
-      return "${pitch}${octave}:${duration}${if (dot) "d" else ""}"
+      return "${pitch}${octave}:(${duration})"
    }
 
    fun intPitch(): Int {
       return octave * 12 + pitch.ordinal
    }
+
+   override fun equals(other: Any?): Boolean {
+      if (this === other) return true
+      if (javaClass != other?.javaClass) return false
+
+      other as Note
+
+      if (pitch != other.pitch) return false
+      if (octave != other.octave) return false
+      if (duration != other.duration) return false
+
+      return true
+   }
+
+   override fun hashCode(): Int {
+      var result = pitch.hashCode()
+      result = 31 * result + octave
+      result = 31 * result + duration.hashCode()
+      return result
+   }
 }
\ No newline at end of file
diff --git a/api/src/main/kotlin/io/smnp/math/Fraction.kt b/api/src/main/kotlin/io/smnp/math/Fraction.kt
new file mode 100644
index 0000000..6987d13
--- /dev/null
+++ b/api/src/main/kotlin/io/smnp/math/Fraction.kt
@@ -0,0 +1,65 @@
+package io.smnp.math
+
+class Fraction(val numerator: Int, val denominator: Int) : Comparable<Fraction> {
+   init {
+      if (denominator == 0) {
+         throw RuntimeException("Invalid fraction: denominator can not be of 0")
+      }
+   }
+
+   operator fun component1() = numerator
+   operator fun component2() = denominator
+
+   val decimal by lazy { numerator.toDouble() / denominator }
+   val inversed by lazy { Fraction(denominator, numerator) }
+
+   val simplified by lazy {
+      val gcd = greatestCommonDenominator(numerator, denominator)
+      Fraction(numerator / gcd, denominator / gcd)
+   }
+
+   private fun greatestCommonDenominator(a: Int, b: Int): Int = if (b == 0) a else greatestCommonDenominator(b, a % b)
+
+   operator fun unaryMinus() = Fraction(-this.numerator, this.denominator)
+
+   operator fun plus(second: Fraction) =
+      if (this.denominator == second.denominator) Fraction(this.numerator + second.numerator, denominator)
+      else {
+         val numerator = numerator * second.denominator + second.numerator * denominator
+         val denominator = denominator * second.denominator
+         Fraction(numerator, denominator)
+      }
+
+   operator fun minus(second: Fraction) = (this + (-second))
+
+   operator fun times(num: Int) = Fraction(numerator * num, denominator)
+
+   operator fun times(second: Fraction) =
+      Fraction(numerator * second.numerator, denominator * second.denominator)
+
+   operator fun div(num: Int) = this.inversed * num
+
+   operator fun div(second: Fraction) = this * second.inversed
+
+   override fun compareTo(other: Fraction) = decimal.compareTo(other.decimal)
+
+   override fun toString() =
+      this.simplified.let { if (it.denominator == 1) it.numerator.toString() else "${it.numerator}/${it.denominator}" }
+
+   override fun equals(other: Any?): Boolean {
+      if (other !is Fraction) {
+         return false
+      }
+
+      val (aNum, aDen) = this.simplified
+      val (bNum, bDen) = other.simplified
+
+      return aNum == bNum && aDen == bDen
+   }
+
+   companion object {
+      fun of(int: Int): Fraction {
+         return Fraction(int, 1)
+      }
+   }
+}
\ No newline at end of file
diff --git a/api/src/main/kotlin/io/smnp/type/model/Value.kt b/api/src/main/kotlin/io/smnp/type/model/Value.kt
index 61bdd0b..dde361a 100644
--- a/api/src/main/kotlin/io/smnp/type/model/Value.kt
+++ b/api/src/main/kotlin/io/smnp/type/model/Value.kt
@@ -101,8 +101,7 @@ data class Value(val type: DataType, val value: Any, val properties: Map<String,
             DataType.NOTE, value, hashMapOf(
                Pair("pitch", string(value.pitch.toString())),
                Pair("octave", int(value.octave)),
-               Pair("duration", int(value.duration)),
-               Pair("dot", bool(value.dot))
+               Pair("duration", float((value.duration.numerator / value.duration.denominator).toFloat()))
             )
          )
       }
diff --git a/app/src/main/kotlin/io/smnp/dsl/token/tokenizer/NoteTokenizer.kt b/app/src/main/kotlin/io/smnp/dsl/token/tokenizer/NoteTokenizer.kt
index 5d50a55..30b4ec5 100644
--- a/app/src/main/kotlin/io/smnp/dsl/token/tokenizer/NoteTokenizer.kt
+++ b/app/src/main/kotlin/io/smnp/dsl/token/tokenizer/NoteTokenizer.kt
@@ -4,73 +4,70 @@ import io.smnp.data.entity.Note
 import io.smnp.data.enumeration.Pitch
 import io.smnp.dsl.token.model.entity.TokenizerOutput
 import io.smnp.dsl.token.model.enumeration.TokenType
+import io.smnp.math.Fraction
 
 class NoteTokenizer : Tokenizer {
-    override fun tokenize(input: String, current: Int, line: Int): TokenizerOutput {
-        var consumedChars = 0
-        var notePitch: String
-        var octave: Int? = null
-        var duration: String? = null
-        var dot = false
-        var rawValue = ""
+   override fun tokenize(input: String, current: Int, line: Int): TokenizerOutput {
+      var consumedChars = 0
+      var notePitch: String
+      var octave: Int? = null
+      var duration: String? = null
+      var dot = false
+      var rawValue = ""
 
-        // Note literal start symbol
-        if(input[current] == '@') {
-            rawValue += input[current+consumedChars]
+      // Note literal start symbol
+      if (input[current] == '@') {
+         rawValue += input[current + consumedChars]
+         consumedChars += 1
+
+         // Note basic pitch
+         if (listOf('c', 'd', 'e', 'f', 'g', 'a', 'h', 'b').contains(input[current + consumedChars].toLowerCase())) {
+            rawValue += input[current + consumedChars]
+            notePitch = input[current + consumedChars].toString()
             consumedChars += 1
 
-            // Note basic pitch
-            if(listOf('c', 'd', 'e', 'f', 'g', 'a', 'h', 'b').contains(input[current+consumedChars].toLowerCase())) {
-                rawValue += input[current+consumedChars]
-                notePitch = input[current+consumedChars].toString()
-                consumedChars += 1
-
-                // Flat or sharp
-                if(current+consumedChars < input.length && listOf('b', '#').contains(input[current+consumedChars])) {
-                    rawValue += input[current+consumedChars]
-                    notePitch += input[current+consumedChars]
-                    consumedChars += 1
-                }
-
-                // Octave
-                if(current+consumedChars < input.length && "\\d".toRegex().matches(input[current+consumedChars].toString())) {
-                    rawValue += input[current+consumedChars]
-                    octave = input[current+consumedChars].toString().toInt()
-                    consumedChars += 1
-                }
-
-                // Duration start symbol
-                if(current+consumedChars < input.length && input[current+consumedChars] == ':') {
-                    rawValue += input[current+consumedChars]
-                    duration = ""
-                    consumedChars += 1
-                    while(current+consumedChars < input.length && "\\d".toRegex().matches(input[current+consumedChars].toString())) {
-                        rawValue += input[current+consumedChars]
-                        duration += input[current+consumedChars]
-                        consumedChars += 1
-                    }
-
-                    if(duration.isEmpty()) {
-                        return TokenizerOutput.NONE
-                    }
-                    dot = (current+consumedChars < input.length && input[current+consumedChars] == 'd')
-
-                    if(dot) {
-                        rawValue += input[current+consumedChars]
-                        consumedChars += 1
-                    }
-                }
-
-                val note = Note.Builder()
-                    .pitch(Pitch.parse(notePitch))
-                    .dot(dot)
-                octave?.let { note.octave(it) }
-                duration?.let { note.duration(it.toInt()) }
-
-                return TokenizerOutput.produce(consumedChars, note.build(), rawValue, TokenType.NOTE, line, current)
+            // Flat or sharp
+            if (current + consumedChars < input.length && listOf('b', '#').contains(input[current + consumedChars])) {
+               rawValue += input[current + consumedChars]
+               notePitch += input[current + consumedChars]
+               consumedChars += 1
             }
-        }
 
-        return TokenizerOutput.NONE
-    }
+            // Octave
+            if (current + consumedChars < input.length && "\\d".toRegex().matches(input[current + consumedChars].toString())) {
+               rawValue += input[current + consumedChars]
+               octave = input[current + consumedChars].toString().toInt()
+               consumedChars += 1
+            }
+
+            // Duration start symbol
+            if (current + consumedChars < input.length && input[current + consumedChars] == ':') {
+               rawValue += input[current + consumedChars]
+               duration = ""
+               consumedChars += 1
+               while (current + consumedChars < input.length && "\\d".toRegex().matches(input[current + consumedChars].toString())) {
+                  rawValue += input[current + consumedChars]
+                  duration += input[current + consumedChars]
+                  consumedChars += 1
+               }
+
+               if (duration.isEmpty()) {
+                  return TokenizerOutput.NONE
+               }
+               dot = (current + consumedChars < input.length && input[current + consumedChars] == 'd')
+
+               if (dot) {
+                  rawValue += input[current + consumedChars]
+                  consumedChars += 1
+               }
+            }
+
+            val note = Note(Pitch.parse(notePitch), octave ?: 4, Fraction(1, duration?.toInt() ?: 4), dot)
+
+            return TokenizerOutput.produce(consumedChars, note, rawValue, TokenType.NOTE, line, current)
+         }
+      }
+
+      return TokenizerOutput.NONE
+   }
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/io/smnp/evaluation/evaluator/SumOperatorEvaluator.kt b/app/src/main/kotlin/io/smnp/evaluation/evaluator/SumOperatorEvaluator.kt
index 76542f9..ebeb0ba 100644
--- a/app/src/main/kotlin/io/smnp/evaluation/evaluator/SumOperatorEvaluator.kt
+++ b/app/src/main/kotlin/io/smnp/evaluation/evaluator/SumOperatorEvaluator.kt
@@ -1,5 +1,6 @@
 package io.smnp.evaluation.evaluator
 
+import io.smnp.data.entity.Note
 import io.smnp.dsl.ast.model.node.Node
 import io.smnp.dsl.ast.model.node.SumOperatorNode
 import io.smnp.dsl.ast.model.node.TokenNode
@@ -11,8 +12,12 @@ import io.smnp.error.PositionException
 import io.smnp.error.ShouldNeverReachThisLineException
 import io.smnp.evaluation.model.entity.EvaluatorOutput
 import io.smnp.evaluation.util.NumberUnification.unify
-import io.smnp.type.enumeration.DataType
+import io.smnp.math.Fraction
+import io.smnp.type.enumeration.DataType.*
 import io.smnp.type.model.Value
+import io.smnp.type.model.Value.Companion.list
+import io.smnp.type.model.Value.Companion.note
+import io.smnp.type.model.Value.Companion.string
 
 class SumOperatorEvaluator : Evaluator() {
    override fun supportedNodes() = listOf(SumOperatorNode::class)
@@ -34,20 +39,20 @@ class SumOperatorEvaluator : Evaluator() {
    }
 
    private fun plus(lhs: Value, plusNode: Node, rhs: Value, environment: Environment): Value {
-      return if (areNumeric(lhs, rhs))
-         unify(lhs, rhs, int = { (l, r) -> Value.int(l + r) }, float = { (l, r) -> Value.float(l + r) })
-      else if (lhs.type == DataType.STRING)
-         Value.string(lhs.value as String + rhs.value.toString())
-      else if (areLists(lhs, rhs))
-         Value.list(lhs.value as List<Value> + rhs.value as List<Value>)
-      else throw PositionException(
-         EnvironmentException(
-            EvaluationException(
-               "The ${lhs.typeName} and ${rhs.typeName} are not supported by + operator"
-            ),
-            environment
-         ), plusNode.position
-      )
+      return when {
+         areNumeric(lhs, rhs) -> unify(lhs, rhs, int = { (l, r) -> Value.int(l + r) }, float = { (l, r) -> Value.float(l + r) })
+         lhs.type == STRING -> string(lhs.value as String + rhs.value.toString())
+         areLists(lhs, rhs) -> list(lhs.value as List<Value> + rhs.value as List<Value>)
+         lhs.type == NOTE && rhs.type == INT -> note(lhs.value as Note + Fraction(1, rhs.value as Int))
+         else -> throw PositionException(
+            EnvironmentException(
+               EvaluationException(
+                  "The ${lhs.typeName} and ${rhs.typeName} are not supported by + operator"
+               ),
+               environment
+            ), plusNode.position
+         )
+      }
    }
 
    private fun minus(lhs: Value, minusNode: Node, rhs: Value, environment: Environment): Value {
@@ -68,5 +73,5 @@ class SumOperatorEvaluator : Evaluator() {
    }
 
    private fun areNumeric(lhs: Value, rhs: Value) = lhs.type.isNumeric() && rhs.type.isNumeric()
-   private fun areLists(lhs: Value, rhs: Value) = lhs.type == DataType.LIST && rhs.type == DataType.LIST
+   private fun areLists(lhs: Value, rhs: Value) = lhs.type == LIST && rhs.type == LIST
 }
\ No newline at end of file
diff --git a/modules/lang/src/main/kotlin/io/smnp/ext/lang/constructor/NoteConstructor.kt b/modules/lang/src/main/kotlin/io/smnp/ext/lang/constructor/NoteConstructor.kt
index 24b3a23..8047a88 100644
--- a/modules/lang/src/main/kotlin/io/smnp/ext/lang/constructor/NoteConstructor.kt
+++ b/modules/lang/src/main/kotlin/io/smnp/ext/lang/constructor/NoteConstructor.kt
@@ -5,6 +5,7 @@ import io.smnp.callable.function.FunctionDefinitionTool
 import io.smnp.callable.signature.Signature.Companion.simple
 import io.smnp.data.entity.Note
 import io.smnp.data.enumeration.Pitch
+import io.smnp.math.Fraction
 import io.smnp.type.enumeration.DataType.*
 import io.smnp.type.matcher.Matcher.Companion.ofType
 import io.smnp.type.model.Value
@@ -18,7 +19,7 @@ class NoteConstructor : Function("Note") {
          ofType(BOOL)
       ) body { _, (pitchString, octave, duration, dot) ->
          val pitch = Pitch.parse((pitchString.value as String).toLowerCase())
-         val note = Note(pitch, octave.value as Int, duration.value as Int, dot.value as Boolean)
+         val note = Note(pitch, octave.value as Int, Fraction(1, duration.value as Int), dot.value as Boolean)
          Value.note(note)
       }
    }
diff --git a/modules/midi/src/main/kotlin/io/smnp/ext/function/MidiHelpFunction.kt b/modules/midi/src/main/kotlin/io/smnp/ext/function/MidiHelpFunction.kt
index b2750e4..63e8040 100644
--- a/modules/midi/src/main/kotlin/io/smnp/ext/function/MidiHelpFunction.kt
+++ b/modules/midi/src/main/kotlin/io/smnp/ext/function/MidiHelpFunction.kt
@@ -7,6 +7,7 @@ import io.smnp.data.entity.Note
 import io.smnp.data.enumeration.Pitch
 import io.smnp.error.CustomException
 import io.smnp.ext.midi.Midi
+import io.smnp.math.Fraction
 import io.smnp.type.enumeration.DataType.*
 import io.smnp.type.matcher.Matcher.Companion.ofType
 import io.smnp.type.matcher.Matcher.Companion.optional
@@ -33,8 +34,8 @@ class MidiHelpFunction : Function("midiHelp") {
       ) body { environment, args ->
          val instrument = args[0].value as Int
          val bpm = args.getOrNull(1)?.value as Int? ?: 120
-         val begin = args.getOrNull(2) ?: Value.note(Note(Pitch.C, 1, 4, false))
-         val end = args.getOrNull(3) ?: Value.note(Note(Pitch.H, 9, 4, false))
+         val begin = args.getOrNull(2) ?: Value.note(Note(Pitch.C, 1, Fraction(1, 4), false))
+         val end = args.getOrNull(3) ?: Value.note(Note(Pitch.H, 9, Fraction(1, 4), false))
          val channel = args.getOrNull(4)?.value as Int? ?: 1
 
          if(channel > 16) {
diff --git a/modules/midi/src/main/kotlin/io/smnp/ext/midi/DefaultSequenceCompiler.kt b/modules/midi/src/main/kotlin/io/smnp/ext/midi/DefaultSequenceCompiler.kt
index 3cf888e..9109896 100644
--- a/modules/midi/src/main/kotlin/io/smnp/ext/midi/DefaultSequenceCompiler.kt
+++ b/modules/midi/src/main/kotlin/io/smnp/ext/midi/DefaultSequenceCompiler.kt
@@ -13,7 +13,7 @@ class DefaultSequenceCompiler : SequenceCompiler() {
       track: Track,
       ppq: Int
    ): Long {
-      val noteDuration = ((if (item.dot) 1.5 else 1.0) * 4L * ppq / item.duration).toLong()
+      val noteDuration = (4L * ppq * item.duration.decimal).toLong()
       val noteOffTick = noteOnTick + noteDuration
       track.add(noteOn(item, channel, noteOnTick))
       track.add(noteOff(item, channel, noteOffTick))
diff --git a/modules/midi/src/main/kotlin/io/smnp/ext/midi/PpqSequenceCompiler.kt b/modules/midi/src/main/kotlin/io/smnp/ext/midi/PpqSequenceCompiler.kt
index 3ff0d8a..2977181 100644
--- a/modules/midi/src/main/kotlin/io/smnp/ext/midi/PpqSequenceCompiler.kt
+++ b/modules/midi/src/main/kotlin/io/smnp/ext/midi/PpqSequenceCompiler.kt
@@ -13,7 +13,7 @@ class PpqSequenceCompiler : SequenceCompiler() {
       track: Track,
       ppq: Int
    ): Long {
-      val noteOffTick = noteOnTick + item.duration
+      val noteOffTick = noteOnTick + item.duration.denominator
       track.add(noteOn(item, channel, noteOnTick))
       track.add(noteOff(item, channel, noteOffTick))
       return noteOffTick