79×42+79+79+57
=79×(42+1+1)+57
=79×44+57
=(80-1)×44+57
=80×44-1×44+57
=3520-44+57
=3520+(57-44)
=3520+13
=3533
怀疑题目出错,貌似应该是
79×42+79+79×57
=79×(42+1+57)
=79×100
=7900
79×42+79+79+57,简便计算?
解:原式=79×42+79×1+79×1+57
=79×(42+1+1)+57
=79×(40+4)+57
=79×40+79×4+57
=3160+316+57
=3476+57
=3433
44个79加57,也就是加上44再加13,相当于44个80再加上13,即原式=79x44+44+13=80x44+13=3520+13=3533。
回答:
79X42十(79X2十57)
=3318十215
=3533
79×42+79+79+57
=79×(42+1+1)+57
=79×44+44+13
=44×(79+1)+13
=3533.