diff --git a/tests/static-toolboxes.test.mjs b/tests/static-toolboxes.test.mjs
index 5a3cd5a..c06fc7b 100644
--- a/tests/static-toolboxes.test.mjs
+++ b/tests/static-toolboxes.test.mjs
@@ -189,6 +189,8 @@ test("toolbox module registry and modules expose expected behavior", async () =>
   assert.match(calculatorModule, /tool-split-entry-label/);
   assert.match(calculatorModule, /copyChecklistImport/);
   assert.match(calculatorModule, /resetCalculator/);
+  assert.match(calculatorModule, /returnToRoot/);
+  assert.match(calculatorModule, /setExpression\(activeParent \? formatResult\(activeParent\.value\) : ""\)/);
   assert.match(calculatorModule, /Quantité non modifiable/);
   assert.match(calculatorModule, /entry\.label \|\| formatResult\(entry\.value\)/);
   assert.match(calculatorModule, /ResizeObserver/);
diff --git a/website/src/features/toolboxes/modules/CalculatorModule.jsx b/website/src/features/toolboxes/modules/CalculatorModule.jsx
index 61613b8..e0fb63b 100644
--- a/website/src/features/toolboxes/modules/CalculatorModule.jsx
+++ b/website/src/features/toolboxes/modules/CalculatorModule.jsx
@@ -93,7 +93,7 @@ export function CalculatorModule({ toolboxId, moduleId, context }) {
         value: result
       }
     ]);
-    setExpression("");
+    setExpression(activeParent ? formatResult(activeParent.value) : "");
     setLabel("");
   }
 
@@ -104,7 +104,10 @@ export function CalculatorModule({ toolboxId, moduleId, context }) {
 
   function deleteEntry(entryId) {
     const deletedIds = new Set([entryId, ...getDescendantIds(data.entries, entryId)]);
-    if (deletedIds.has(activeParentId)) setActiveParentId("");
+    if (deletedIds.has(activeParentId)) {
+      setActiveParentId("");
+      setExpression("");
+    }
     save(data.entries.filter((entry) => !deletedIds.has(entry.id)));
   }
 
@@ -119,6 +122,11 @@ export function CalculatorModule({ toolboxId, moduleId, context }) {
     setActiveParentId("");
   }
 
+  function returnToRoot() {
+    setActiveParentId("");
+    setExpression("");
+  }
+
   async function copyChecklistImport() {
     const text = getEntriesInTreeOrder(data.entries)
       .map((entry) => `${entry.label || formatResult(entry.value)}:${formatResult(entry.value)}`)
@@ -154,7 +162,7 @@ export function CalculatorModule({ toolboxId, moduleId, context }) {
       >
         <div className="tool-split-actions">
           {activeParent && (
-            <button className="tool-split-root-button" type="button" onClick={() => setActiveParentId("")}>
+            <button className="tool-split-root-button" type="button" onClick={returnToRoot}>
               {textContent.rootButton || "Revenir à la racine"}
             </button>
           )}