signed number computation
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1. 100 - 20 = ?

2. 20 - 100 = ?

3. 12 - (-20) = ?

4. (-25) - 40 = ?

5. 40 - (-25) = ?

6. 1+2-3+4-5+6-7+8-9+10-11+12-13+14-15+16-17+18 = ?

7. What is the sum of the first 10 positive integers ?

8. What is the sum of the square of the first 10 positive integers ?

9. 10 + 5 *4 - 6 * (8-3*2) + 12 = ?

10. 2+4+6+8+...+100 = ?