Subtract 4-Digit Numbers Mentally

Step 1 of 4 · The trick

Subtracting a round 10, 100, or 1000? Only ONE digit changes.

Each digit lives in its own column:
K · H · T · O
Subtract 30? Only the tens digit moves.
Subtract 500? Only the hundreds digit moves.

All other columns stay exactly the same.

Step 2 of 4 · 1,234 − 30

1,234 − 30 = ?

aligned to the tens column ↑

3 − 3 = 0

1,234 − 30 = 1,204

Step 3 of 4 · 1,500 − 500

1,500 − 500 = ?

aligned to the hundreds column ↑

5 − 5 = 0

1,500 − 500 = 1,000

Step 4 of 4 · Your turn

Only one digit changes.

🏆

Nice work!

You changed just one digit.