Graph three points on the number line:
a point at -2 1/4
a point at the opposite of -2 1/4
and
a point at the sum of -2 1/4 and its opposite.
1. A point at -2 1/4: (-2.25)
2. A point at the opposite of -2 1/4: 2.25
3. A point at the sum of -2 1/4 and its opposite: -2.25 + 2.25 = 0
Graph:
-2.25 -------- 0 -------- 2.25