1. 直接写出得数。
$1.7+8.3=$ $2-1.05=$ $125×80=$
$0.8-0.07=$ $100×3.25=$ $420÷4=$
$0.24×5=$ $0.25×4=$ $3.3-1.4=$
$0.78+0.13=$ $7500÷1500=$ $1.5×8=$
$0.24×50=$ $3900÷13=$ $34.6-2.8=$

$1.7+8.3=10$
$2-1.05=0.95$
$125×80=10000$
$0.8-0.07=0.73$
$100×3.25=325$
$420÷4=105$
$0.24×5=1.2$
$0.25×4=1$
$3.3-1.4=1.9$
$0.78+0.13=0.91$
$7500÷1500=5$
$1.5×8=12$
$0.24×50=12$
$3900÷13=300$
$34.6-2.8=31.8$

2. 计算下列各题，能简算的要简算。
$17.6×24-17.6×4$ $23.6+23.6×9$
$21.5×0.8-21.5×0.8$ $0.125×0.25×0.8×0.4$
$5.7×9.9$ $28.5-8.5×3.2$
$89.5-0.4×2.5$ $10.1×8.3$
$39.52+5.2+5.08$ $32.8×0.4+17.2×0.4$

$17.6×24-17.6×4$
$=17.6×(24-4)$
$=17.6×20$
$=352$
$23.6+23.6×9$
$=23.6×(1+9)$
$=23.6×10$
$=236$
$21.5×0.8-21.5×0.8$
$=21.5×(0.8-0.8)$
$=21.5×0$
$=0$
$0.125×0.25×0.8×0.4$
$=(0.125×0.8)×(0.25×0.4)$
$=0.1×0.1$
$=0.01$
$5.7×9.9$
$=5.7×(10-0.1)$
$=5.7×10-5.7×0.1$
$=57-0.57$
$=56.43$
$28.5-8.5×3.2$
$=28.5-27.2$
$=1.3$
$89.5-0.4×2.5$
$=89.5-1$
$=88.5$
$10.1×8.3$
$=(10+0.1)×8.3$
$=10×8.3+0.1×8.3$
$=83+0.83$
$=83.83$
$39.52+5.2+5.08$
$=39.52+5.08+5.2$
$=44.6+5.2$
$=49.8$
$32.8×0.4+17.2×0.4$
$=(32.8+17.2)×0.4$
$=50×0.4$
$=20$