To round each number to its greatest place value before multiplying:
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Round 90:
- The greatest place value is the tens place.
- 90 rounded to its greatest place value is 90.
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Round 6.5:
- The greatest place value is the units place (1s).
- 6.5 rounded to its greatest place value is 7.
Now, multiply the rounded numbers:
\[ 90 \times 7 = 630 \]
So, the final answer is 630.