Pre Algebra Questions
Sketch a model and obtain the sum. 3 + (-7)
http://www.mathsisfun.com/number-line.html
To sketch a model and find the sum of 3 + (-7), we can use a number line.
1. Draw a number line with zero in the middle and mark positive numbers to the right and negative numbers to the left.
-3 -2 -1 0 1 2 3 4 5 6 7 8 9 (and so on)
2. Start at the position of 0 on the number line.
3. To represent the number 3, count three positions to the right. Mark this position.
-3 -2 -1 0 1 2 3 4 5 6 7 8 9 (and so on)
↑
4. To represent the number -7, count seven positions to the left. Mark this position.
-3 -2 -1 0 1 2 3 4 5 6 7 8 9 (and so on)
↑ ↑
5. To find the sum of 3 + (-7), start at the position of 3 and move seven positions to the left.
-3 -2 -1 0 1 2 3 4 5 6 7 8 9 (and so on)
↑ ↑
6. The final position is -4. This means that 3 + (-7) is equal to -4.
Therefore, the sum of 3 + (-7) is -4.