K. Mental Arithmetic
Solve these problems without paper and pencil. You may use a number line or mental math. Write down the answers. Explain how you found your answers.
- 7 + 5 =
- 7 + 15 =
- 7 + 75 =
= 10 − 8
= 100 − 8
= 100 − 18
- Explain how solving Questions D and E can help you solve Question F.