Question
Use the product $(a + b) (a – b) = a^2 – b^2$ to evaluate : $9.8 \times 10.2$
✓
Answer
$9.8 \times 10.2 $
$= (10−0.2) (10+0.2)$
$= (10)^2 − (0.2)^{2 }$
$= 100 − 0.04$
$= 99.96$
$= (10−0.2) (10+0.2)$
$= (10)^2 − (0.2)^{2 }$
$= 100 − 0.04$
$= 99.96$
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