①8.03-3.16-3.84
=8.03-(3.16+3.84)
=8.03-7
=1.03
②3780÷35+13×308
=108+13×(300+8)
=108+13×300+13×8
=108+3900+104
=212+3900
=4112
③25×3.2×125
=(25×4)×(0.8×125)
=100×100
=10000
④4÷
-4 5
÷44 5
=4÷0.8-0.8÷4
=5-0.2
=4.8
⑤
×6.7+4.3×0.8-80%4 5
=0.8×6.7+4.3×0.8-0.8×1
=0.8×(6.7+4.3-1)
=0.8×10
=8
⑥(
+1 6
-2 9
)×361 18
=
×36+1 6
×36-2 9
×361 18
=6+8-2
=12