Question

[Thanh Ngọcc]

1. Tính bằng cách thuận tiện nhất:

a) 6,15 : 0,5 + 6,15 : 0,2 + 3 x 6,15

b) 3 giờ 25p x 4 + 1 giờ 35p x 4

c) 6,25 + 8,75 + 3,75 + 1,25

d) 0,215 x 74,24 + 25,76 x 0,215 + 18,5

e) 3/7 : 11/5 + 4/7 : 11/5

g) 7,15 : 0,5 + 7,15 x 9 - 7,15

Answer 1

[HT.Phong (9A5)]

\(a.6,15:0,5+6,15:0,2+3\times6,15\\ =6,15\times2+6,15\times5+6,15\times3\\ =6,15\times\left(2+5+3\right)\\ =6,15\times10\\ =61,5\\ b.3h35p\times4+1h35p\times4\\ =4\times\left(3h25p+1h35p\right)\\ =4\times5h\\ =20h\\ c.6,25+8,75+3,75+1,25\\ =\left(6,25+3,75\right)+\left(8,75+1,25\right)\\ =10+10\\ =20\\ d.0,215\times74,24+25,76\times0,215+18,5\\ =0,215\times\left(74,24+25,76\right)+18,5\\ =0,215\times100+18,5\\ =21,5+18,5\\ =40\\ e.\dfrac{3}{7}:\dfrac{11}{5}+\dfrac{4}{7}:\dfrac{11}{5}\\ =\dfrac{3}{7}\times\dfrac{5}{11}+\dfrac{4}{7}\times\dfrac{5}{11}\\ =\dfrac{5}{11}\times\left(\dfrac{3}{7}+\dfrac{4}{7}\right)\\ =\dfrac{5}{11}\times1\\ =\dfrac{5}{11}\\ g.7,15:0,5+7,15\times9-7,15\\ =7,15\times2+7,15\times9-7,15\\ =7,15\times\left(2+9-1\right)\\ =7,15\times10=71,5\)

Answer 2

[Trịnh Thị Hoài An]

a) 6,15 : 0,5 + 6,15 : 0,2 + 3 x 6,15
= 6,15 x 2 + 6,15 . 5 + 3 x 6,15
= 6,15 x ( 2 + 5 + 3)
= 6,15 x 10
= 61,5