diff --git a/core/deno.json b/core/deno.json
index 0b4705f..668f70f 100644
--- a/core/deno.json
+++ b/core/deno.json
@@ -6,5 +6,5 @@
   },
   "name": "@dalbit-yaksok/core",
   "exports": "./mod.ts",
-  "version": "0.2.0-RC.3"
+  "version": "0.2.0-RC.4"
 }
\ No newline at end of file
diff --git a/core/error/calculation.ts b/core/error/calculation.ts
index 4e15570..7ec2e1d 100644
--- a/core/error/calculation.ts
+++ b/core/error/calculation.ts
@@ -41,3 +41,31 @@ export class InvalidTypeForOperatorError extends YaksokError {
         )}할 수 없어요.`
     }
 }
+
+export class RangeStartMustBeIntegerError extends YaksokError {
+    constructor(props: {
+        tokens?: Token[]
+        resource: {
+            start: ValueType
+        }
+    }) {
+        super(props)
+
+        const startText = valueTypeToText(props.resource.start)
+        this.message = `범위의 시작은 정수여야 해요. ${startText}는 정수가 아니에요.`
+    }
+}
+
+export class RangeEndMustBeIntegerError extends YaksokError {
+    constructor(props: {
+        tokens?: Token[]
+        resource: {
+            end: ValueType
+        }
+    }) {
+        super(props)
+
+        const endText = valueTypeToText(props.resource.end)
+        this.message = `범위의 끝은 정수여야 해요. ${endText}는 정수가 아니에요.`
+    }
+}
diff --git a/core/error/indexed.ts b/core/error/indexed.ts
index 42ddb06..c3c20b3 100644
--- a/core/error/indexed.ts
+++ b/core/error/indexed.ts
@@ -46,7 +46,7 @@ export class ListIndexMustBeGreaterThan1Error extends YaksokError {
 
 export class RangeEndMustBeNumberError extends YaksokError {
     constructor(props: {
-        position?: Position
+        tokens?: Token[]
         resource: {
             end: ValueType
         }
@@ -86,7 +86,6 @@ export class ListIndexTypeError extends YaksokError {
 
 export class RangeStartMustBeNumberError extends YaksokError {
     constructor(props: {
-        position?: Position
         tokens?: Token[]
         resource: {
             start: ValueType
@@ -102,7 +101,6 @@ export class RangeStartMustBeNumberError extends YaksokError {
 export class TargetIsNotIndexedValueError extends YaksokError {
     constructor(props: {
         tokens: Token[]
-
         resource: {
             target: Evaluable
         }
diff --git a/core/node/calculation.ts b/core/node/calculation.ts
index c48ab13..db1bb07 100644
--- a/core/node/calculation.ts
+++ b/core/node/calculation.ts
@@ -20,7 +20,11 @@ import {
 import { Evaluable, Operator, OperatorClass } from './base.ts'
 import { ValueType } from '../value/base.ts'
 import type { Token } from '../prepare/tokenize/token.ts'
-import { InvalidTypeForOperatorError } from '../error/calculation.ts'
+import {
+    InvalidTypeForOperatorError,
+    RangeEndMustBeIntegerError,
+    RangeStartMustBeIntegerError,
+} from '../error/calculation.ts'
 import { YaksokError } from '../error/common.ts'
 import {
     RangeEndMustBeNumberError,
@@ -153,9 +157,15 @@ export class Formula extends Evaluable {
                 if (e instanceof YaksokError && !e.tokens) {
                     if (e instanceof InvalidTypeForOperatorError) {
                         e.tokens = mergedTokens
-                    } else if (e instanceof RangeStartMustBeNumberError) {
+                    } else if (
+                        e instanceof RangeStartMustBeNumberError ||
+                        e instanceof RangeStartMustBeIntegerError
+                    ) {
                         e.tokens = termsWithToken[i - 1].tokens
-                    } else if (e instanceof RangeEndMustBeNumberError) {
+                    } else if (
+                        e instanceof RangeEndMustBeNumberError ||
+                        e instanceof RangeEndMustBeIntegerError
+                    ) {
                         e.tokens = termsWithToken[i + 1].tokens
                     } else if (e instanceof RangeStartMustBeLessThanEndError) {
                         e.tokens = mergedTokens
diff --git a/core/node/operator.ts b/core/node/operator.ts
index 864c812..cf1cff9 100644
--- a/core/node/operator.ts
+++ b/core/node/operator.ts
@@ -4,6 +4,8 @@ import {
     RangeEndMustBeNumberError,
     RangeStartMustBeLessThanEndError,
     RangeStartMustBeNumberError,
+    RangeStartMustBeIntegerError,
+    RangeEndMustBeIntegerError,
 } from '../error/index.ts'
 import { Token } from '../prepare/tokenize/token.ts'
 
@@ -445,9 +447,11 @@ export class RangeOperator extends Operator {
         this.assertProperOperands(operands)
 
         const [start, end] = operands
-        const items = new Array(end.value - start.value + 1)
+        const roundedStart = Math.round(start.value)
+        const roundedEnd = Math.round(end.value)
+        const items = new Array(roundedEnd - roundedStart + 1)
             .fill(null)
-            .map((_, index) => new NumberValue(start.value + index))
+            .map((_, index) => new NumberValue(roundedStart + index))
 
         return new ListValue(items)
     }
@@ -465,25 +469,39 @@ export class RangeOperator extends Operator {
     private assertProperStartType(
         start: ValueType,
     ): asserts start is NumberValue {
-        if (start instanceof NumberValue) return
+        if (!(start instanceof NumberValue)) {
+            throw new RangeStartMustBeNumberError({
+                resource: {
+                    start,
+                },
+            })
+        }
 
-        throw new RangeStartMustBeNumberError({
-            position: this.tokens[0].position,
-            resource: {
-                start,
-            },
-        })
+        if (!Number.isInteger(start.value)) {
+            throw new RangeStartMustBeIntegerError({
+                resource: {
+                    start,
+                },
+            })
+        }
     }
 
     private assertProperEndType(end: ValueType): asserts end is NumberValue {
-        if (end instanceof NumberValue) return
+        if (!(end instanceof NumberValue)) {
+            throw new RangeEndMustBeNumberError({
+                resource: {
+                    end,
+                },
+            })
+        }
 
-        throw new RangeEndMustBeNumberError({
-            position: this.tokens[0].position,
-            resource: {
-                end,
-            },
-        })
+        if (!Number.isInteger(end.value)) {
+            throw new RangeEndMustBeIntegerError({
+                resource: {
+                    end,
+                },
+            })
+        }
     }
 
     private assertRangeStartLessThanEnd(start: number, end: number) {
diff --git a/deno.json b/deno.json
index d44aa9b..35c733f 100644
--- a/deno.json
+++ b/deno.json
@@ -22,7 +22,7 @@
         "test",
         "monaco-language-provider"
     ],
-    "version": "0.2.0-RC.3",
+    "version": "0.2.0-RC.4",
     "tasks": {
         "apply-version": "deno run --allow-read --allow-write apply-version.ts",
         "publish": "deno task --recursive test && deno publish --allow-dirty"
diff --git a/monaco-language-provider/deno.json b/monaco-language-provider/deno.json
index d460d2e..379e675 100644
--- a/monaco-language-provider/deno.json
+++ b/monaco-language-provider/deno.json
@@ -4,5 +4,5 @@
   },
   "name": "@dalbit-yaksok/monaco-language-provider",
   "exports": "./mod.ts",
-  "version": "0.2.0-RC.3"
+  "version": "0.2.0-RC.4"
 }
\ No newline at end of file
diff --git a/quickjs/deno.json b/quickjs/deno.json
index ccd7d2b..126ab26 100644
--- a/quickjs/deno.json
+++ b/quickjs/deno.json
@@ -9,5 +9,5 @@
     "check-deploy": "deno publish --dry-run --allow-dirty",
     "test": "deno test --quiet --allow-net --allow-read --parallel & deno lint & deno task check-deploy"
   },
-  "version": "0.2.0-RC.3"
+  "version": "0.2.0-RC.4"
 }
\ No newline at end of file
diff --git a/runtest.ts b/runtest.ts
index e3e2533..62ec98d 100644
--- a/runtest.ts
+++ b/runtest.ts
@@ -1,9 +1,5 @@
 import { yaksok } from '@dalbit-yaksok/core'
 
 await yaksok(`
-약속, (10) 말하기
-반복
-        결과: "안녕하세요"
-
-말하기 보여주기
+3 ~ 8.3 보여주기
 `)
diff --git a/test/errors/loop.test.ts b/test/errors/loop.test.ts
index 2ca7031..c3e0879 100644
--- a/test/errors/loop.test.ts
+++ b/test/errors/loop.test.ts
@@ -8,6 +8,8 @@ import {
     RangeEndMustBeNumberError,
     RangeStartMustBeLessThanEndError,
     RangeStartMustBeNumberError,
+    RangeStartMustBeIntegerError,
+    RangeEndMustBeIntegerError,
     TargetIsNotIndexedValueError,
     ListIndexMustBeGreaterThan1Error,
 } from '../../core/error/index.ts'
@@ -75,6 +77,31 @@ Deno.test('Range end must be number', async () => {
     }
 })
 
+Deno.test('Range start must be an integer', async () => {
+    try {
+        await yaksok(`1.5 ~ 5`)
+        unreachable()
+    } catch (e) {
+        assertIsError(e, RangeStartMustBeIntegerError)
+    }
+
+    try {
+        await yaksok(`1.5 ~ 3.2`)
+        unreachable()
+    } catch (e) {
+        assertIsError(e, RangeStartMustBeIntegerError)
+    }
+})
+
+Deno.test('Range end must be an integer', async () => {
+    try {
+        await yaksok(`1 ~ 5.5`)
+        unreachable()
+    } catch (e) {
+        assertIsError(e, RangeEndMustBeIntegerError)
+    }
+})
+
 Deno.test('Index set target is must be indexable', async () => {
     try {
         await yaksok(`목록: 5