十二分之五减八分之一加二十一分之十六减八分之三的简便运算?
5/12-1/8+16/21-3/8
=5/12+16/21-1/8-3/8
=35/84+64/84-42/84
=99/84-42/84
=57/84
没啥简便的计算方法。
5/12-1/8+16/21
=10/24-3/24+16/21
=7/24+16/21
=49/(24×7)+128/(21×8)
=177/168
=1又9/168
=1又3/56
5/12-1/8+16/21-3/8
=5/12+16/21-(1/8+3/8)
5/12+16/21-1/2
=35/84+64/84-42/84
=99/84-42/84
=57/84
=19/28