1. Simplify 24 ÷ [ 52 – (13 + 7)]

2. Use grouping symbols(parentheses) to make the following statement true.

25 – 8 · 3 = 51

3. Find 6.8% of 500.

4. Find the mean of the following numbers: 63, 67, 70, 78, 74, 72

5. One number is 10.

The unknown number is less than 10.

The GCF of the numbers is 2.

Their LCM is 30.

What is the unknown number?