计算
$1.63 + 0.37 =$
$3.4 + 1.6 =$
$0.8 + 0.2 =$
$0.7 + 2.5 + 1.3 =$
$2.8 + 4.9 + 3.2 =$
$3.6 - 1.8 + 6.4 =$
$0.9 + 9.9 =$
$7.3 - 3.5 + 0.7 =$
$4.4 - 0.9 + 1.6 =$
$7.7 - 6.6 + 6.6 =$
$0.17 + 0.83 =$
$2.4 - 1.6 - 0.4 =$
$0.85 + 2.09 + 0.15 =$
$4 - 0.94 - 0.06 =$
$0.83 + 1.21 =$
$1 - 0.07 + 0.03 =$
$0.08 + 0.29 + 0.02 =$
$9.9 + 9.99 =$

2,5,1,4.5,10.9,8.2,10.8,4.5,5.1,7.7,1,0.4,3.09,3,2.04,0.96,0.39,19.89

1.63 + 0.37 = 2
3.4 + 1.6 = 5
0.8 + 0.2 = 1
0.7 + 2.5 + 1.3 = (0.7 + 1.3) + 2.5 = 2 + 2.5 = 4.5
2.8 + 4.9 + 3.2 = (2.8 + 3.2) + 4.9 = 6 + 4.9 = 10.9
3.6 - 1.8 + 6.4 = (3.6 + 6.4) - 1.8 = 10 - 1.8 = 8.2
0.9 + 9.9 = 10.8
7.3 - 3.5 + 0.7 = (7.3 + 0.7) - 3.5 = 8 - 3.5 = 4.5
4.4 - 0.9 + 1.6 = (4.4 + 1.6) - 0.9 = 6 - 0.9 = 5.1
7.7 - 6.6 + 6.6 = 7.7 + ( -6.6 + 6.6 ) = 7.7 + 0 = 7.7
0.17 + 0.83 = 1
2.4 - 1.6 - 0.4 = 2.4 - (1.6 + 0.4) = 2.4 - 2 = 0.4
0.85 + 2.09 + 0.15 = (0.85 + 0.15) + 2.09 = 1 + 2.09 = 3.09
4 - 0.94 - 0.06 = 4 - (0.94 + 0.06) = 4 - 1 = 3
0.83 + 1.21 = 2.04
1 - 0.07 + 0.03 = 0.93 + 0.03 = 0.96
0.08 + 0.29 + 0.02 = (0.08 + 0.02) + 0.29 = 0.1 + 0.29 = 0.39
9.9 + 9.99 = 19.89

怎样简便就怎样计算
$3.78 + 2.02 + 0.98$
$10.1 - 2.54 - 4.46$
$6.32 + 5.8 - 3.32$
$9.2 + 10.34 + 20.8 + 9.66$
$10.1 - (1.02 + 5.1) - 3.98$

1. $6.78$
2. $3.1$
3. $8.8$
4. $50$
5. $0$

1. 对于 $3.78 + 2.02 + 0.98$：
利用加法结合律，先计算 $2.02 + 0.98$，再与 $3.78$ 相加。
$3.78 + 2.02 + 0.98 = 3.78 + (2.02 + 0.98) = 3.78 + 3 = 6.78$
2. 对于 $10.1 - 2.54 - 4.46$：
利用减法性质，先计算 $2.54 + 4.46$，再从 $10.1$ 中减去这个和。
$10.1 - 2.54 - 4.46 = 10.1 - (2.54 + 4.46) = 10.1 - 7 = 3.1$
3. 对于 $6.32 + 5.8 - 3.32$：
利用加法交换律和结合律，先计算 $6.32 - 3.32$，再加上 $5.8$。
$6.32 + 5.8 - 3.32 = 6.32 - 3.32 + 5.8 = 3 + 5.8 = 8.8$
4. 对于 $9.2 + 10.34 + 20.8 + 9.66$：
利用加法交换律和结合律，分别计算 $9.2 + 20.8$ 和 $10.34 + 9.66$，再将两个和相加。
$9.2 + 10.34 + 20.8 + 9.66 = (9.2 + 20.8) + (10.34 + 9.66) = 30 + 20 = 50$
5. 对于 $10.1 - (1.02 + 5.1) - 3.98$：
先计算括号内的和，再利用减法性质，计算 $10.1 - 5.1 - 1.02 - 3.98$，然后利用减法结合律计算$1.02+3.98$，最后得出结果。
$10.1 - (1.02 + 5.1) - 3.98 =10.1 - 5.1- 1.02 - 3.98=5-(1.02+3.98)=0$