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I agree.
70 * 7 = ?
73 * 7 = ?
70 * 7 = ?
73 * 7 = ?
To find the exact answer of 73 x 7, we multiply 73 by 7 using long multiplication:
73
x 7
-----
511
+ 365
-----
511
The exact answer is 511.
Now let's compare it with Marcia's estimate. She claims that her estimate will be less than the exact answer.
Since we estimate by rounding numbers, let's round 73 to the nearest ten, which is 70, and round 7 to the nearest ten, which is 10.
Now we multiply the rounded numbers: 70 x 10 = 700
As we can see, Marcia's estimated product of 73 x 7 (700) is indeed less than the exact answer (511).
Therefore, Marcia is correct in her statement that her estimate is less than the exact answer.