Step 1 of 4 · The rule
A number is divisible by 3 if and only if the sum of its digits is divisible by 3.
N ÷ 3 works only when (sum of digits) ÷ 3 works.
Why? Every power of 10 leaves remainder 1 when divided by 3 (10=9+1, 100=99+1, ...), so only the digits matter.
Step 2 of 4 · Worked: 4 7 1
Is 471 divisible by 3?
Add the digits. Check if the sum is divisible by 3.
4 + 7 + 1 = 12
12 ÷ 3 = 4 ✓ (exact)
YES — 471 is divisible by 3
Step 3 of 4 · Worked: 1 2 7
Is 127 divisible by 3?
Same approach — sum the digits, check the sum.
1 + 2 + 7 = 10
10 ÷ 3 = 3 remainder 1 ✗
NO — 127 is NOT divisible by 3
Step 4 of 4 · Your turn
Divisible by 3?
🏆
Nice work!
You aced the divisibility checks.