Add decimals including negatives

Line up the decimal points to add or subtract. The sign rules are the same as for integers.

1. Evaluate: −9.0 + (−6.8)
2. Evaluate: −2.3 + 2.5
3. Evaluate: 0.7 + 0.8
4. Evaluate: −6.2 + (−10.0)
5. Evaluate: −0.7 + 6.4
6. Evaluate: 10.4 + (−0.5)
7. Evaluate: −10.6 + (−12.7)
8. Evaluate: 12.2 + 0.9
9. Evaluate: 4.5 + (−3.45)
10. Evaluate: 7.2 + 17.26
11. Evaluate: 3.3 + 0.76
12. Evaluate: −1.2 + (−4.67)
13. Evaluate: 27.6 + (−32.97)
14. Evaluate: 22.1 + 35.84
15. Evaluate: 30.1 + 31.34
16. Evaluate: −32.8 + 5.22
17. Evaluate: 34.2 + 68.72
18. Evaluate: 59.1 + (−13.69)
19. Evaluate: 25.9 + 5.76
20. Evaluate: −55.0 + 0.42