Tính nhanh a) 4/7 + 3/4 + 2/7 + 5/4 +1/7 b) -5/7 + 3/4 + -1/5 + -2/7 +1/4
Giải thích
a) 47+34+27+54+17=47+27+17+34+54=3
b) −57+34+−15+−27+14=−57+−27+34+14+−15=−1+1+−15=−15
a) 47+34+27+54+17=47+27+17+34+54=3
b) −57+34+−15+−27+14=−57+−27+34+14+−15=−1+1+−15=−15