Question

Use inverse relationships and properties of equality to solve 38.9 – g = 14.8.


Use tiles to show the steps and reasoning to solve the equation.

Answer 1

We want to solve 38.9 − g = 14.8 for g using inverse operations and maintaining equality.

Start (tile model):
- Think of 38.9 as a pile of + tiles (38.9 positive units) and −g as a single negative g tile on the left.
- The right side is a pile of + tiles totaling 14.8.

Equation with tile labels:
[+38.9] [−g] = [+14.8]

Step 1 — add g to both sides (inverse of subtracting g). This cancels the −g tile on the left:
[+38.9] [−g] [+g] = [+14.8] [+g]
Left: −g and +g cancel → [+38.9] = [+14.8] [+g]

Step 2 — remove 14.8 from both sides (inverse of adding 14.8). Subtract 14.8 tiles from each side:
[+38.9] [−14.8] = [+14.8] [+g] [−14.8]
Left becomes +24.1, right becomes +g:
[+24.1] = [g]

So g = 24.1.

Check: 38.9 − 24.1 = 14.8 ✅