《2025年启东中学作业本七年级数学上册人教版》

1. 口算:
(1)$(-3)+(-9)=$-12 (2)$(-4.7)+3.9=$-0.8
(3)$(-4)+6=$2 (4)$(-4)+4=$0
(5)$6+(-6)=$0 (6)$0+(-6)=$-6
(7)$(-0.9)+1.5=$0.6 (8)$\frac {1}{2}+(-\frac {2}{3})=$$-\frac{1}{6}$
(9)$(-10)+6=$-4 (10)$(+12)+(-4)=$8
(11)$(-2.6)+(+1.2)=$-1.4 (12)$(-3.2)+(+5.2)=$2
(13)$(-0.9)+(-2.7)=$-3.6 (14)$\frac {2}{5}+(-\frac {3}{5})=$$-\frac{1}{5}$
(15)$(-6.9)+2.3=$-4.6 (16)$(-1.5)+9=$7.5

答案：
(1)-12
(2)-0.8
(3)2
(4)0
(5)0
(6)-6
(7)0.6
(8)$-\frac{1}{6}$
(9)-4
(10)8
(11)-1.4
(12)2
(13)-3.6
(14)$-\frac{1}{5}$
(15)-4.6
(16)7.5

2. 计算:
(1)$(-12)+\frac {1}{7};$ (2)$3.14+(-5.2);$ (3)$(-4.1)+(-15.61);$
(4)$(-9.2)+(-1\frac {3}{5});$ (5)$\frac {3}{10}+(-\frac {2}{5});$ (6)$(-1\frac {3}{4})+3\frac {1}{3}.$

答案：
(1)$-11\frac{6}{7}$
(2)-2.06
(3)-19.71
(4)$-10\frac{4}{5}$
(5)$-\frac{1}{10}$
(6)$\frac{19}{12}$