简便运算九又五分之四乘4.25加四又四分之一/六 三十一又八分之三乘七十二又十三分之九除以三十一又八分之三

[ (9+ 4/5) X 4.25 + (4+ 1/4) ] / 6
= [ (9+ 0.8) X 4.25 + 4.25 ] / 6
= [ 4.25 X (9.8 +1) ] / 6
= 4.25 X 10.8 / 6
= 4.25 X 1.8
= 8.5 X 0.9
= 8.5 - 0.85
= 7.5 + 0.15
= 7.65
(31+ 3/8) X (72+ 9/13) / (31+ 6/8) / 0.25
= (248/8 + 3/8) X (72+ 9/13) / (124/4 + 3/4) / (1/4)
= (251/ 8) X 9 X (8+ 1/13) / (127/ 4) / (1/4)
= (251/ 8) X 9 X (105/ 13) X (4/ 127) X 4
= (251 X 9 X 105 X 4 X 4) / (8 X 13 X 127)
写错没有,好像看不出能怎么巧算