**Lesson Steps**:

1. Find a common Denominator by multiplying them together

10 * 15 = 150

2. Multiply the Numerators

7/10 * 15 = 105/150

2/15 * 10 = 20/150

3. Subtract the factions

105/150 - 20/150 = 85/150

4. Simplify by finding the least common multiple between 85 and 150 which is 5

85/5 = 17

150 / 5 = 30

The answer is 17/30

**Answer**:

17/30

**Grade**: 9

**Level**: Highschool

**Subject**: Math

**Topic**: Fractions