Tính nhanh: 4/7+3/4+2/7+5/4+1/7
Giải thích
a)47+27+17+34+54=3b)−57+−27+−15+34+14=−15
c)513+813+−57+−2041+−2141=−57d)128+328+314+−114+−17=17e)12+−12+−23+23+34+−34+−45+45+56+−56=0
a)47+27+17+34+54=3b)−57+−27+−15+34+14=−15
c)513+813+−57+−2041+−2141=−57d)128+328+314+−114+−17=17e)12+−12+−23+23+34+−34+−45+45+56+−56=0