Question

Which of the following can be used as a hint to solve the following equation? Identify the complete equation.
45 – 15 = ?

• A. $15=10+5;45–15=31$
• B. $15=30–15;45–15=20$
• C. $15=10+5;45–15=30$
• D. $15=8+9;45–15=25$

Answer 1

The correct option is C $15=10+5;45–15=30$

Detailed step-by-step solution:
Let us solve the problem 45 – 15 = ? using the decomposition strategy.
To subtract 15 from 45, we can break apart 15 into 10 and 5.

Therefore, we can conclude that 15 = 10 + 5 can be used as a hint because here 15 is broken apart into 10 and 5. So, the complete equation is 45 – 15 = 30.

Hence, Option D is correct.