Tính: a) 1/3 + 4/7 + 5/21 - 1 = ......... b) (2 2/7 + 1/6) * 1 2/5 - 3
Giải thích
a) 13+47+521−1=721+1221+521−2121=321=17
b) 227+16×125−3=167+16×75−3=9642+742×75−3=10342×75−3=10330−9030=1330
a) 13+47+521−1=721+1221+521−2121=321=17
b) 227+16×125−3=167+16×75−3=9642+742×75−3=10342×75−3=10330−9030=1330