Question

tính biểu thức

a)7/20-(5/8-2/5)

b)5/6+(5/6-1/4)

c)9/10-(2/5+3/10)+7/20

Answer 1

b. 5/6 + ( 5/6 -1/4 )= 5/6 + 7/12= 17/12= 1/5/12

Answer 2

a, 7/20 - ( 5/8-2/5 )= 7/20-9/40=1/8

Answer 3

c. 9/10-( 2/5 + 3/10 ) + 7/20= 9/10- 7/10+7/20=2/10+ 7/20= 11/20