45+6*9-90 20-2*8+66 51-8*5-11 81:7*9 32:4*6 49:7*8 9*8+8 7*3+7 6*9+6

Let's calculate each expression step-by-step.

1. 45 + 6 * 9 - 90

   • First, calculate \(6 * 9 = 54\)
   • Then, \(45 + 54 - 90 = 99 - 90 = 9\)

2. 20 - 2 * 8 + 66

   • First, calculate \(2 * 8 = 16\)
   • Then, \(20 - 16 + 66 = 4 + 66 = 70\)

3. 51 - 8 * 5 - 11

   • First, calculate \(8 * 5 = 40\)
   • Then, \(51 - 40 - 11 = 11 - 11 = 0\)

4. 81 ÷ 7 * 9

   • First, calculate \(81 ÷ 7 ≈ 11.57\) (but keep the exact fraction for accuracy)
   • Then, \(11.57 * 9 ≈ 104.14\) (exact calculation: \((81/7) * 9 = \frac{729}{7} = 104.14\))

5. 32 ÷ 4 * 6

   • First, calculate \(32 ÷ 4 = 8\)
   • Then, \(8 * 6 = 48\)

6. 49 ÷ 7 * 8

   • First, calculate \(49 ÷ 7 = 7\)
   • Then, \(7 * 8 = 56\)

7. 9 * 8 + 8

   • First, calculate \(9 * 8 = 72\)
   • Then, \(72 + 8 = 80\)

8. 7 * 3 + 7

   • First, calculate \(7 * 3 = 21\)
   • Then, \(21 + 7 = 28\)

9. 6 * 9 + 6

   • First, calculate \(6 * 9 = 54\)
   • Then, \(54 + 6 = 60\)

Summary of Solutions:

1. \(9\)
2. \(70\)
3. \(0\)
4. \(~104.14\) (or \( \frac{729}{7} \))
5. \(48\)
6. \(56\)
7. \(80\)
8. \(28\)
9. \(60\)