To estimate the product of 115 × 9, we follow these steps:
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Round the factors:
- 115 is rounded to 120.
- 9 is rounded to 10.
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Multiply the rounded numbers:
- 120 × 10.
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Multiply the first digits:
- 1 x 1 = 1.
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Count how many zeros are in the factors:
- 120 has 2 zeros, and 10 has 1 zero, so there are a total of 3 zeros.
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Combine the result:
- 1 followed by 3 zeros gives us 1,000.
So the estimated product of 115 × 9 is 1,000.