8.1 X 7 - 53.01 / 9.3 + (3+ 2/5)
= 56.7 - 1767 / 310 + 3.4
= 56.7 - ( 1550 + 217 ) / 310 + 3.4
= 56.7 - 5.7 + 3.4
= 51 + 3.4
= 54.4
( 7.2 + 7.2 + 7.2 + 7.2 ) X 2.5
= 7.2 X 4 X 2.5
= 72 X 4 X 0.25
= 72 X 1
= 72
( 93.5 - 3.5 X 7.2 ) / ( 1/2 - 1/4 )
= ( 93.5 - 3.5 - 3.5 X 6.2 ) / ( 1/4 )
= ( 90 - 7 X 3.1 ) X 4
= ( 90 - 21.7 ) X 4
= 68.3 X 4
= 136.6 X 2
= 273.2( 93.5 - 3.5 X 7.2 ) / ( 1/2 - 1/4 )这个能再详细给我把到二步的式子写出来吗？( 93.5 - 3.5 X 7.2 ) / ( 1/2 - 1/4 )= [ 93.5 - 3.5 X ( 1 + 6.2 ) ] / ( 2/4 - 1/4 )= [ 93.5 - 3.5X1 - 3.5 X 6.2 ] / (1/4)= [ 93.5 - 3.5 - 3.5 X 2 X 3.1 ] X 4= ( 90 - 7 X 3.1 ) X 4= ( 90 - 21.7 ) X 4= 68.3 X 2 X 2= 136.6 X 2= 273.2