Question

вычислите выбрав удобный порядок действий.42+61+28+39+30. 4×9×5×2×25.

Answer 1

1)42+28=70+30=100+61=161+39=200
2)2*5=10*25=250*4=1000*9=9000

Answer 2

42+61+28+39+30=(42+28)+(61+39)+30=70+100+30=
=(70+30)+100=200
4×9×5×2×25=9*(5*2)*(25*4)=9*10*100=9000