diff --git a/.idea/workspace.xml b/.idea/workspace.xml
index 26f368c..f002281 100644
--- a/.idea/workspace.xml
+++ b/.idea/workspace.xml
@@ -4,9 +4,9 @@
     <option name="autoReloadType" value="SELECTIVE" />
   </component>
   <component name="ChangeListManager">
-    <list default="true" id="b30e2810-c4c1-4aad-b134-794e52cc1c7d" name="Changes" comment="fix: compilation">
+    <list default="true" id="b30e2810-c4c1-4aad-b134-794e52cc1c7d" name="Changes" comment="chore: printRunningSum">
       <change beforePath="$PROJECT_DIR$/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/src/pages/number/sum/service.ts" beforeDir="false" afterPath="$PROJECT_DIR$/src/pages/number/sum/service.ts" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/src/pages/number/sum/sum.service.test.ts" beforeDir="false" afterPath="$PROJECT_DIR$/src/pages/number/sum/sum.service.test.ts" afterDir="false" />
     </list>
     <option name="SHOW_DIALOG" value="false" />
     <option name="HIGHLIGHT_CONFLICTS" value="true" />
@@ -176,15 +176,7 @@
       <workItem from="1719166718305" duration="1783000" />
       <workItem from="1719168519203" duration="17675000" />
       <workItem from="1719197816332" duration="1453000" />
-      <workItem from="1719273044735" duration="8860000" />
-    </task>
-    <task id="LOCAL-00004" summary="feat: example tools">
-      <option name="closed" value="true" />
-      <created>1718822309352</created>
-      <option name="number" value="00004" />
-      <option name="presentableId" value="LOCAL-00004" />
-      <option name="project" value="LOCAL" />
-      <updated>1718822309352</updated>
+      <workItem from="1719273044735" duration="9001000" />
     </task>
     <task id="LOCAL-00005" summary="feat: Split string">
       <option name="closed" value="true" />
@@ -570,7 +562,15 @@
       <option name="project" value="LOCAL" />
       <updated>1719281605999</updated>
     </task>
-    <option name="localTasksCounter" value="53" />
+    <task id="LOCAL-00053" summary="chore: printRunningSum">
+      <option name="closed" value="true" />
+      <created>1719282009150</created>
+      <option name="number" value="00053" />
+      <option name="presentableId" value="LOCAL-00053" />
+      <option name="project" value="LOCAL" />
+      <updated>1719282009150</updated>
+    </task>
+    <option name="localTasksCounter" value="54" />
     <servers />
   </component>
   <component name="TypeScriptGeneratedFilesManager">
@@ -591,7 +591,6 @@
     <option name="CHECK_CODE_SMELLS_BEFORE_PROJECT_COMMIT" value="false" />
     <option name="CHECK_NEW_TODO" value="false" />
     <option name="ADD_EXTERNAL_FILES_SILENTLY" value="true" />
-    <MESSAGE value="feat: tools normalized" />
     <MESSAGE value="feat: search tools" />
     <MESSAGE value="fix: deploy message" />
     <MESSAGE value="chore: tools by category" />
@@ -616,7 +615,8 @@
     <MESSAGE value="feat: string to morse" />
     <MESSAGE value="feat: sum numbers init" />
     <MESSAGE value="fix: compilation" />
-    <option name="LAST_COMMIT_MESSAGE" value="fix: compilation" />
+    <MESSAGE value="chore: printRunningSum" />
+    <option name="LAST_COMMIT_MESSAGE" value="chore: printRunningSum" />
   </component>
   <component name="XSLT-Support.FileAssociations.UIState">
     <expand />
diff --git a/src/pages/number/sum/sum.service.test.ts b/src/pages/number/sum/sum.service.test.ts
index c18748e..1a3b21b 100644
--- a/src/pages/number/sum/sum.service.test.ts
+++ b/src/pages/number/sum/sum.service.test.ts
@@ -1,6 +1,64 @@
-import { expect, describe, it } from 'vitest';
-// import { } from './service';
-//
-// describe('sum', () => {
-//
-// })
\ No newline at end of file
+import { describe, it, expect } from 'vitest';
+import { compute } from './service';
+
+describe('compute function', () => {
+  it('should correctly sum numbers in smart extraction mode', () => {
+    const input = 'The 2 cats have 4 and 7 kittens';
+    const result = compute(input, 'smart', false, ',');
+    expect(result).toBe('13');
+  });
+
+  it('should correctly sum numbers with custom delimiter', () => {
+    const input = '2,4,7';
+    const result = compute(input, 'delimiter', false, ',');
+    expect(result).toBe('13');
+  });
+
+  it('should return running sum in smart extraction mode', () => {
+    const input = 'The 2 cats have 4 and 7 kittens';
+    const result = compute(input, 'smart', true, ',');
+    expect(result).toBe('2\n6\n13\n');
+  });
+
+  it('should return running sum with custom delimiter', () => {
+    const input = '2,4,7';
+    const result = compute(input, 'delimiter', true, ',');
+    expect(result).toBe('2\n6\n13\n');
+  });
+
+  it('should handle empty input gracefully in smart mode', () => {
+    const input = '';
+    const result = compute(input, 'smart', false, ',');
+    expect(result).toBe('0');
+  });
+
+  it('should handle empty input gracefully in delimiter mode', () => {
+    const input = '';
+    const result = compute(input, 'delimiter', false, ',');
+    expect(result).toBe('0');
+  });
+
+  it('should handle input with no numbers in smart mode', () => {
+    const input = 'There are no numbers here';
+    const result = compute(input, 'smart', false, ',');
+    expect(result).toBe('0');
+  });
+
+  it('should handle input with no numbers in delimiter mode', () => {
+    const input = 'a,b,c';
+    const result = compute(input, 'delimiter', false, ',');
+    expect(result).toBe('0');
+  });
+
+  it('should ignore non-numeric parts in delimiter mode', () => {
+    const input = '2,a,4,b,7';
+    const result = compute(input, 'delimiter', false, ',');
+    expect(result).toBe('13');
+  });
+
+  it('should handle different separators', () => {
+    const input = '2;4;7';
+    const result = compute(input, 'delimiter', false, ';');
+    expect(result).toBe('13');
+  });
+});