On this worksheet we will investigate how addition and subtraction of a constant will affect an inequality.
The sketch below shows a number line with the numbers A and B marked. You can add the same number to both A and B by dragging the slider, point P.

1. In starting position, which is larger, A or B? Fill in the first line of the table below. Use the inequality symbols < and >.
2. Drag point P to add 2 to both numbers. Now which is larger, A+P or B+P? Fill in the second line of the table.
3. How can you use the slider to subtract the same number from both A and B? Subtract 3 and fill in the third line of the table.
4. Fill in the rest of the Table
Operation........................Position of A+P...............Inequality symbol...............Position of B+P
Starting number.........................1........................................???....................................2
Add 2
Subtract 3
Add −2
Subtract −4
What happens to the relative position of numbers A+P and B+P when you add or subtract a positive number? A negative number? Does anything happen to the direction of the inequality symbol?