Question

bài 1 Tính

a) 13+21.5- (198:11-8)

b) (64+115+36) -25.8

Bài2 Tính nhanh

a) 75.8.15.3

b) 15.6.4.125.8

c) 6+8+10+12+14+16+18

 

Answer 1

a, 13 + 105 - ( 18 - 8 ) 

 = 13 + 105 - 10 

 = 118 - 10

 = 108

b, ( 64 + 36 +115 ) - 200

  = ( 100 + 115 ) - 200

 = 215 - 200

 = 15

 

Answer 2

Bài 1:

a)13+21.5-(198:11-8)

= 13+105-(10-8)

= 118-10

= 108.

b)(64+115+36)-25.8

= (100+115)-200

= 215-200

= 15.

Bài 2 :

a)75.8.15.3

= (75.15).8.3

= 1125.8.3

= 9000.3

= 27000.

b)15.6.4.125.8

= (15.6.4).(125.8)

= 360.1000

= 360000.

c)6+8+10+12+14+16+18

= (6+8+10)+(12+18)+(14+16)

= 24+30+30

= 84.

Answer 3

a)75.8.15.3

=(75.8).(15.3)

=600.45

=27000

b)15.6.4.125.8

=(15.6.4).(125.8)

=360.1000

=360000

c)6+8+10+12+14+16+18

=(6+14)+(8+12)+(10+16+18)

=20+20+44

=40+44

=84