diff --git a/curriculum/challenges/english/08-coding-interview-prep/project-euler/problem-19-counting-sundays.english.md b/curriculum/challenges/english/08-coding-interview-prep/project-euler/problem-19-counting-sundays.english.md
index 16298c1156..54f0300cb3 100644
--- a/curriculum/challenges/english/08-coding-interview-prep/project-euler/problem-19-counting-sundays.english.md
+++ b/curriculum/challenges/english/08-coding-interview-prep/project-euler/problem-19-counting-sundays.english.md
@@ -23,8 +23,8 @@ How many Sundays fell on the first of the month during the twentieth century (1
 tests:
   - text: '<code>countingSundays(1943, 1946)</code> should return 6.'
     testString: 'assert.strictEqual(countingSundays(1943, 1946), 6, "<code>countingSundays(1943, 1946)</code> should return 6.");'
-  - text: '<code>countingSundays(1995, 2000)</code> should return 9.'
-    testString: 'assert.strictEqual(countingSundays(1995, 2000), 9, "<code>countingSundays(1995, 2000)</code> should return 9.");'
+  - text: '<code>countingSundays(1995, 2000)</code> should return 10.'
+    testString: 'assert.strictEqual(countingSundays(1995, 2000), 10, "<code>countingSundays(1995, 2000)</code> should return 10.");'
   - text: '<code>countingSundays(1901, 2000)</code> should return 171.'
     testString: 'assert.strictEqual(countingSundays(1901, 2000), 171, "<code>countingSundays(1901, 2000)</code> should return 171.");'
 
@@ -61,7 +61,7 @@ function countingSundays(firstYear, lastYear) {
   let sundays = 0;
 
   for (let year = firstYear; year <= lastYear; year++) {
-    for (let month = 1; month <= 12; month++) {
+    for (let month = 0; month <= 11; month++) {
       const thisDate = new Date(year, month, 1);
       if (thisDate.getDay() === 0) {
         sundays++;