Carla used a calculator and found out that 31.5 \times 21.68=682.92. Explain to her why the answer is correct by reasoning about the size of the factors.

pancha3

pancha3

Answered question

2021-08-07

Carla used a calculator and found out that 31.5×21.68=682.92. She is suspicious about her answer because it doesnt

Answer & Explanation

Brittany Patton

Brittany Patton

Skilled2021-08-08Added 100 answers

Step 1
31.5×21.68=682.92
We know that 3×2=6
Also, 30×20=600
Thus solution should be >600.
Step 2
Also, 8 (which is the last decimal digit of 21.68) ×5 (which is the last decimal digit of 31.5) =40. This 0 cancels the 3rd decimal digit in the answer. Thus, the solution has 2 decimal digits.

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