Question

Tính bằng cách thuận tiện:
 a)25×47×4×2                                  b) 865×99+865
c)472×1002-472-472                    d)2478+10275+7522-275

Answer 1

\(a,25\times47\times4\times2=\left(25\times4\right)\times\left(47\times2\right)=100\times94=9400\\ b,865\times99+865=865\times\left(99+1\right)=865\times100=86500\\ c,472\times1002-472-472=472\times\left(1002-1-1\right)=472\times1000=472000\\ d,2478+10275+7522-275=\left(2478+7522\right)+\left(10275-275\right)=10000+10000=20000\)

Answer 2

a 9400

b 86500

c 472000

d 20000