Stage 8 of 20

Two-Digit Plus Single (With Carry)

When adding a single digit pushes the ones past 9, carry one to the tens column. This merges your carrying skill with place value understanding.

What You'll Learn

For 47 + 8: ones give 7 + 8 = 15. Write down the 5, carry 1 to tens. 4 + 1 = 5. Answer: 55.

Use the complement method: 47 + 8 → 47 needs 3 to reach 50, leaving 5 from the 8. Answer: 55.

The complement method is often faster because you work with round numbers (50, 60, 70) as stepping stones.

Always check: if you carried correctly, the answer should be about 10 more than a no-carry estimate.

• Round up to the next ten first, then add what remains.
• Say the tens transition aloud: "forty-seven… fifty… fifty-five."
• Practice with numbers ending in 7, 8, or 9 — they trigger carrying most often.

Work through each problem mentally. Click "Show Answer" when you're ready to check.