Question

Tính nhanh

a) -7624+(1543+7624)                b) (27-514)-(486-73)

Answer 1

a)-7624+(1543+7624)=-7624+1543+7624=(-7624+7624)+1543=0+1543=1543

b)(27-514)-(486-73)=27-514-486+73=27+(-514)+(-486)+73=(27+73)+[(-514)+(-486)]=100+(-1000)=-900

Answer 2

a)-7624+(1543+7624)

=(-7624+7624)+1543

=0+1543

=1543

b)(27-514)-(486-73)

=(27+73)-(514+486)

=100-1000

=-900