Question
Find the square of the number $39$ without actual multiplication.
✓
Answer
$39^2=(30+9)^2$
$= (30 + 9)(30 + 9)$
$= 30(30 + 9) + 9(30 + 9)$
$= 30^2+30 \times 9+9 \times 30+9^2$
$= 900 + 270 + 270 + 81 = 1521$
$= (30 + 9)(30 + 9)$
$= 30(30 + 9) + 9(30 + 9)$
$= 30^2+30 \times 9+9 \times 30+9^2$
$= 900 + 270 + 270 + 81 = 1521$
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