Question

Tính nhanh \(\dfrac{45.16-17}{28+45.15}\)

Answer 1

Ta có:

45 . 16 - 17 = 45. (15 +1) - 17

= 45 . 15 + 1.45 - 17

= 45 . 15 + (45 - 17)

= 45 . 15 + 28

vậy \(\dfrac{45.16-17}{45.15+28}=\dfrac{45.15+28}{45.15+28}=1\)

Answer 2

\(\dfrac{45.16-17}{28+45.15}\)

= \(\dfrac{45.\left(15+1\right)-17}{28+45.15}\)

= \(\dfrac{45.15+\left(45-17\right)}{28+45.15}\)

= \(\dfrac{45.15+27}{27+45.15}\)

= 1

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