Question

bai1:tinh nham bang cach hop li :

a,7.8.39+56.30+14.4.31

b,175+35-275+100

c,350.7+140.7+7:7

 

Answer 1

a) 7.8.39+56.30+14.4.31

= 56.39+56.30+56.31

= 56.(39+30+31)

= 56.100

=5600

b) 175+35-275+100

= (175-275)+100+35

= -100+100+35

= 0+35

=35

c) 350.7+140.7+7:7

= 7.(350+140)+1

= 7.490+1

= 3430+1

=3431

Answer 2

a, 7.8.39+56.30+14.4.31

=56.39+56.30+56.31

=56.(39+30+31)

=56.100

=5600

b, 175+35-275+100

=(175+100-275)+35

=(375-375)+35

=0+35

=35

c, 350.7+140.7+7:7

=7.(350+140)+7:7

=7.490+1

=3430+1

=3431

Answer 3

a, 5600

b, 35

c, 3431

Answer 4

 a ) 2184 + 1680 + 1736 = 5600

b ) -65 +100 = 35 

c ) 2450 + 980 + 1 = 2431