扬帆起航
$2.3-0.5=$ $9.7-8.8=$ $1.4-0.5=$
$1.6-0.9=$ $5.8-4.9=$ $4-3.3=$
$80-5.4=$ $6-3.4=$ $7.6-1.8=$
$9.8-5.9=$ $10-5.7=$ $0.6-0.3=$

2.3-0.5=1.8
9.7-8.8=0.9
1.4-0.5=0.9
1.6-0.9=0.7
5.8-4.9=0.9
4-3.3=0.7
80-5.4=74.6
6-3.4=2.6
7.6-1.8=5.8
9.8-5.9=3.9
10-5.7=4.3
0.6-0.3=0.3

乘风破浪
$0.3+0.8=$ $2.3+0.9=$ $1.9+0.5=$
$6.7+0.9=$ $8.4+0.7=$ $4.5+0.9=$
$8.9+8.8=$ $7.3+0.9=$ $10.7+8.9=$
$45.6+0.9=$ $9.5+3.9=$ $25.2+1.9=$
$55.9+5.6=$ $10.3+0.9=$ $50.6+0.9=$
$0.7+2.8=$ $5.8+3.4=$ $70.3+0.9=$
$8.4-0.7=$ $3.6+0.8=$ $32+24.7=$
$5.9+4.8=$ $10.3+0.8=$ $89-8.3=$

$0.3 + 0.8 = 1.1$
$2.3 + 0.9 = 3.2$
$1.9 + 0.5 = 2.4$
$6.7 + 0.9 = 7.6$
$8.4 + 0.7 = 9.1$
$4.5 + 0.9 = 5.4$
$8.9 + 8.8 = 17.7$
$7.3 + 0.9 = 8.2$
$10.7 + 8.9 = 19.6$
$45.6 + 0.9 = 46.5$
$9.5 + 3.9 = 13.4$
$25.2 + 1.9 = 27.1$
$55.9 + 5.6 = 61.5$
$10.3 + 0.9 = 11.2$
$50.6 + 0.9 = 51.5$
$0.7 + 2.8 = 3.5$
$5.8 + 3.4 = 9.2$
$70.3 + 0.9 = 71.2$
$8.4 - 0.7 = 7.7$
$3.6 + 0.8 = 4.4$
$32 + 24.7 = 56.7$
$5.9 + 4.8 = 10.7$
$10.3 + 0.8 = 11.1$
$89 - 8.3 = 80.7$

圆满返航
小红在计算$6.43$加一个一位小数时，错误地把两个小数的末尾对齐，相加得到$7$。正确的结果应该是多少？
秘籍点拨 根据一个加数$=$和$-$另一个加数，可以求出另一个加数。
评价：需要努力() 基本过关() 非常出色()

7 - 6.43 = 0.57
0.57 × 10 = 5.7
6.43 + 5.7 = 12.13
正确结果是12.13。