75乘以59减去74+42乘以74的简便方法75*59-74+42*74=（74+1）*59+74*（42-1）=74*59+59+74*41=74*（59+41）+59=74*100+59=7459
题目可能是74*59-74+42*74…74*59-74+42*74=74*(58+1)-74+42*74=74*58+74*1-74+42*74=74*(58+42)=74*100=7400
