13. \( 1 / 4 \) of \( 100= \) 14. \( 9 \times 8=(2 \times 8)+(\quad \times 8) \) 15. \( 90-11= \) 16. How many metres of fencing would need for a block 40 m by 12 m ? What is the number before 9000 ?

Calculate the value by following steps: - step0: Calculate: \(90-11\) - step1: Subtract the numbers: \(79\) Calculate or simplify the expression \( 40 * 2 + 12 * 2 \). Calculate the value by following steps: - step0: Calculate: \(40\times 2+12\times 2\) - step1: Multiply the numbers: \(80+12\times 2\) - step2: Multiply the numbers: \(80+24\) - step3: Add the numbers: \(104\) Calculate or simplify the expression \( 2 * 8 \). Calculate the value by following steps: - step0: Calculate: \(2\times 8\) - step1: Multiply the numbers: \(16\) Calculate or simplify the expression \( 9000 - 1 \). Calculate the value by following steps: - step0: Calculate: \(9000-1\) - step1: Subtract the numbers: \(8999\) Calculate or simplify the expression \( 9 * 8 \). Calculate the value by following steps: - step0: Calculate: \(9\times 8\) - step1: Multiply the numbers: \(72\) Calculate or simplify the expression \( 1/4 * 100 \). Calculate the value by following steps: - step0: Calculate: \(\frac{1}{4}\times 100\) - step1: Reduce the numbers: \(1\times 25\) - step2: Simplify: \(25\) Here are the solutions to your problems: 13. \( \frac{1}{4} \) of \( 100 \) is calculated as follows: \[ \frac{1}{4} \times 100 = 25 \] 14. For \( 9 \times 8 \): \[ 9 \times 8 = 72 \] We can express this as: \[ (2 \times 8) + ( \quad \times 8) \implies (2 \times 8) + (7 \times 8) = 72 \] So, the missing number is \( 7 \). 15. The calculation for \( 90 - 11 \) is: \[ 90 - 11 = 79 \] 16. To find the amount of fencing needed for a block measuring \( 40 \, m \) by \( 12 \, m \): \[ \text{Perimeter} = 2 \times (40 + 12) = 2 \times 52 = 104 \, m \] Lastly, the number before \( 9000 \) is: \[ 9000 - 1 = 8999 \] In summary: - 13: \( 25 \) - 14: \( 7 \) - 15: \( 79 \) - 16: \( 104 \, m \) - Number before \( 9000 \): \( 8999 \)