(1)24÷(
-1 2
)1 3
=24÷
1 6
=144
答:这个数是144;
(2)
÷(3 10
-15 22
×3 4
)2 11
=
÷(3 10
-15 22
)3 22
=
÷3 10
6 11
=
11 20
答:商是
;11 20
(3)(24×
)÷(5 8
-7 12
)1 6
=15÷
5 12
=36
答:商是36;
(4)设这个数是x
25%x-
x=51 8
12.5%x=5
12.5%x÷12.5=5÷12.5%
x=40
答:这个数是40.