Mathematical Operations Questions and Answers

Answer: C

Correct answer: 24

Substituting gives \[ 20 + 8 - 8 \div 4 \times 2. \] The division and multiplication are taken first, left to right: \( 8\div4 = 2 \), then \( 2\times2 = 4 \). What remains is \( 20 + 8 - 4 = 24 \). Working strictly left to right instead would give 22, which is why the order of operations has to be respected after the symbols are replaced.

Answer: D

Correct answer: None of these

Substituting turns the expression into one whose value falls outside every figure offered, so the answer is none of them. The stem’s list of definitions has been damaged - one sign appears against two different operations - but on any consistent reading of it the result is a value the three numbered options do not contain.

Answer: D

Correct answer: 2 + 4 ÷ 6 = 8

Making both interchanges in this equation turns the plus into a divide and the divide into a plus, and swaps the 2 and the 4, giving \[ 4 \div 2 + 6 = 2 + 6 = 8, \] which is correct. In each of the other three the same two interchanges leave a left side that does not match the number on the right.

Answer: C

Correct answer: + and –, 3 and 5

Interchanging the two signs and the numbers 3 and 5 turns \( 3 + 5 - 2 \) into \( 5 - 3 + 2 \), which is 4 as required. Swapping 2 with 3 instead gives \( 2 - 5 + 3 = 0 \), and swapping 2 with 5 gives \( 3 - 2 + 5 = 6 \) - so only the third interchange works.

Answer: D

Correct answer: 36 -6 + 3 × 5 ÷ 3 = 74

Substituting in this option gives \[ 36 \times 6 \div 3 + 5 - 3. \] Multiplication and division first, left to right: \( 36\times6 = 216 \), then \( 216\div3 = 72 \). Then \( 72 + 5 - 3 = 74 \), which matches. The other three options do not balance once their signs are replaced.

Answer: C

Correct answer: 8 R 8 P 8 S 8 Q 8 = 57

Substituting gives \[ 8 \times 8 + 8 \div 8 - 8 = 64 + 1 - 8 = 57. \] The multiplication and the division are evaluated before the addition and subtraction, which is what makes the middle term contribute 1 rather than being folded into a running total.

Answer: C

Correct answer: 20 < 2 + 10 ÷ 4 – 6 × 100

Substituting gives \( 20 \div 2 \times 10 - 4 + 6 \) on the left, and the final symbol means greater than. Working left to right through the divide and multiply: \( 20\div2 = 10 \), \( 10\times10 = 100 \), then \( 100 - 4 + 6 = 102 \). Since 102 exceeds 100 the statement holds.

Answer: D

Correct answer: 28

Substituting gives \[ 45 \div 9 \times 3 + 15 - 2. \] Division and multiplication first, left to right: \( 45\div9 = 5 \), \( 5\times3 = 15 \). Then \( 15 + 15 - 2 = 28 \).

Answer: A

Correct answer: 30 – 6 + 5 × 4 ÷ 2 = 27.

Substituting in this option gives \[ 30 \div 6 \times 5 + 4 - 2. \] Taking the divide and multiply first: \( 30\div6 = 5 \), \( 5\times5 = 25 \). Then \( 25 + 4 - 2 = 27 \), which matches the stated value. The other three fail once their symbols are replaced.

Answer: C

Correct answer: 30

Substituting gives \[ 25 + 12 \times 2 \div 4 - 1. \] The multiplication and division are taken first, left to right: \( 12\times2 = 24 \), \( 24\div4 = 6 \). Then \( 25 + 6 - 1 = 30 \).