Question

[Nguyễn Thị Hà My]

tính bằng cách thuận tiện nhất

a (976 +865)+ 135= ......

891 + ( 799 + 109 = .....

b (2/5 + 7/9) + 3/5 = ......

19/11 +( 8/13 +3/11 =...

c 16,88 + 9,76 +3,12 = ...

72,68 +17,16 + 82,64 = ...

Answer 1

[Noo Phuoc Thinh]

9976+865)+135=976+(865+135)=976+1000=1976

891+(799+109)=(891+109)+799=1000+799=1799

(2/5+1/9)+3/5=(2/5+3/5)+1/9=1+1/9=9/9+1/9=10/9

19/11+(8/13+3/11)=(19/11+3/11)+8/13=22/11+8/13=22/11+8/13=2+8/13=26/13+8/13=34/13

16.88+9.76+3.12=(16.88+3.12)+9.76=20+9.76=29.76

72.68+17.16+82.64=72.68+(17.16+82.64)=72.68+100=172.68

Answer 2

[Phạm Thị Mai Anh]

(976+865)+135=976+(865+135)

                      =976+1000=1976