(1)2.5×(2.9+2.9+2.9+2.9),
=2.5×4×2.9,
=10×2.9,
=29;
(2)(
-2 3
×5 9
)÷3 8
,7 16
=(
-2 3
)÷5 24
,7 16
=
÷11 24
,7 16
=1
;1 21
(3)(
+1 6
-1 9
)×36,1 12
=
×36+1 6
×36-1 9
×36,1 12
=6+4-3,
=10-3,
=7;
(4)4÷
-4 9
÷16,4 9
=9-
,1 36
=8
.35 36