Tính nhanh a) 1/5 + 2/9 + 4/5 + -11/9 + 3/7 b) -7/31 + 24/17 + 7/31
Giải thích
a) 15+29+45+−119+37=15+45+29+−119+37=1+(−1)+37=37
b) −731+2417+731+−517+1=−731+731+2417+−517+1=0+1917+1=3617
a) 15+29+45+−119+37=15+45+29+−119+37=1+(−1)+37=37
b) −731+2417+731+−517+1=−731+731+2417+−517+1=0+1917+1=3617