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Specific Tricks

Level 25 / mastery

Sub via add (- near-round)

3 visual steps / subtract near round

1. Use round

235 - 991. Use roundSubtract the nearby round number.1235 - 100 = 1352add back 13answer 136
Subtract the nearby round number.

Subtract the nearby round number.

2. Add back

235 - 992. Add backAdd back the extra amount.1235 - 100 = 1352add back 13answer 136
Add back the extra amount.

Add back the extra amount.

3. Final answer

235 - 993. Final answerKeep the adjusted total. Read answer answer 136Keep the adjusted total.
Keep the adjusted total.

Keep the adjusted total.

Practice Level 25

Name the shape first; the shortcut stays small.

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