Let's work it out together.
Work through one checkpoint at a time. Your answer area opens after the reasoning.
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Checkpoint 1
Estimate with nearby multiples: 9 × 10 = 90 and 9 × 20 = 180.
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Checkpoint 2
Now find the greatest multiple that does not exceed 140: 9 × 15 = 135.
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Checkpoint 3
Subtract to get 5, then check 9 × 15 + 5 = 140 and 5 < 9.