1. 直接写出得数。
$0.7×0.07=$ $0.4×0.8=$ $0.17+0.32=$
$0.52×2=$ $0.4×1.9=$ $0.35×20=$
$0.22÷100=$ $0.8×40=$ $1.2-0.7=$
$0.7×0.9=$ $8×12.5=$ $0.08×12.5=$
$0.12÷10=$ $0.63+2.7=$ $3.2-0.9=$

0.7×0.07=0.049 0.4×0.8=0.32 0.17+0.32=0.49
0.52×2=1.04 0.4×1.9=0.76 0.35×20=7
0.22÷100=0.0022 0.8×40=32 1.2-0.7=0.5
0.7×0.9=0.63 8×12.5=100 0.08×12.5=1
0.12÷10=0.012 0.63+2.7=3.33 3.2-0.9=2.3

(1)运用乘法分配律：$5.6×(10+0.1)=5.6×(\_\_\_\_\_\_)+5.6×(\_\_\_\_\_\_)$

$5.6×(10+0.1)=5.6×(10)+5.6×(0.1)$

(2)运用乘法结合律：$(0.375×2.5)×4=0.375×(\_\_\_\_\_\_×\_\_\_\_\_\_)$

$(0.375×2.5)×4=0.375×(2.5×4)$

(3)运用加法交换律和结合律：
$2.15+3.26+5.85+1.04=(\_\_\_\_\_\_+\_\_\_\_\_\_)+(\_\_\_\_\_\_+\_\_\_\_\_\_)$

$2.15+3.26+5.85+1.04=(2.15+5.85)+(3.26+1.04)$
$=8+4.3$
$=12.3$

3. 计算下列各题，能简算的要简算。
$5.28+3.4+4.72$ $98.52-14.3-25.7$
$1.25×0.46×8$ $4.7+0.3×5.08$
$99×2.67+2.67$ $3.6×18.4-3.6×8.4$
$0.25×32×1.25$ $8.8×0.6+0.4$

$5.28+3.4+4.72$
$=5.28+4.72+3.4$
$=10+3.4$
$=13.4$
$98.52-14.3-25.7$
$=98.52-(14.3+25.7)$
$=98.52-40$
$=58.52$
$1.25×0.46×8$
$=1.25×8×0.46$
$=10×0.46$
$=4.6$
$4.7+0.3×5.08$
$=4.7+1.524$
$=6.224$
$99×2.67+2.67$
$=(99+1)×2.67$
$=100×2.67$
$=267$
$3.6×18.4-3.6×8.4$
$=3.6×(18.4-8.4)$
$=3.6×10$
$=36$
$0.25×32×1.25$
$=0.25×(4×8)×1.25$
$=(0.25×4)×(1.25×8)$
$=1×10$
$=10$
$8.8×0.6+0.4$
$=5.28+0.4$
$=5.68$