1. 直接写出得数。
3.9+1.7=
35.09+4.1=
10.43-3.77=
40-39.06=
18.35+1.65=
5.7+0.43=
12.02-1.1=
62-5.3=
9.7-7=
3.7+9.6=
74-2.6=
16×60=
65-13.2=
16-7.8=
810÷90=

1. 5.6
2. 39.19
3. 6.66
4. 0.94
5. 20
6. 6.13
7. 10.92
8. 56.7
9. 2.7
10. 13.3
11. 71.4
12. 960
13. 51.8
14. 8.2
15. 9

2. 递等式计算。(能简算的要简算)
$22-(3.6+7.39)$
$27.18-9.1-1.9$
$45.23-4.77-5.23$
$19.87-(8.87+0.6)$
$4.37+8.5+0.63+11.5$
$13.37+5.42-2.37+4.58$
$8.6-2.82+3.14$
$10.27-0.34+1.73-2.66$

1. 22-(3.6+7.39)=22-10.99=11.01
2. 27.18-9.1-1.9=27.18-(9.1+1.9)=27.18-11=16.18
3. 45.23-4.77-5.23=45.23-(4.77+5.23)=45.23-10=35.23
4. 19.87-(8.87+0.6)=19.87-8.87-0.6=11-0.6=10.4
5. 4.37+8.5+0.63+11.5=(4.37+0.63)+(8.5+11.5)=5+20=25
6. 13.37+5.42-2.37+4.58=(13.37-2.37)+(5.42+4.58)=11+10=21
7. 8.6-2.82+3.14=5.78+3.14=8.92
8. 10.27-0.34+1.73-2.66=(10.27+1.73)-(0.34+2.66)=12-3=9