Step 1: 21 = 3*7 (composite). Step 2: 33 = 3*11 (composite). Step 3: 51 = 3*17 (composite). Step 4: 29 has no divisors other than 1 and itself; hence it is prime.

Step 1: Divide magnitudes: 42/6 = 7. Step 2: A positive divided by a negative is negative. Step 3: Result is -7.

Step 1: The product of two negatives is positive. Step 2: 2*7 = 14. Step 3: Therefore -2 * (-7) = 14.

Step 1: Subtracting a negative is adding: -3 - (-8) = -3 + 8. Step 2: -3 + 8 = 5.

Step 1: Any nonzero number to the zero power equals 1. Step 2: Therefore 10^0 = 1 by the zero exponent rule.

Step 1: Use exponent rules for same base: 2^3 * 2^4 = 2^(3+4) = 2^7. Step 2: Compute 2^7 = 128.

Step 1: The grouping changes but the order remains the same. Step 2: This is the associative property of addition, not commutative (which swaps order) or distributive (which multiplies over addition). Step 3: Identity property involves adding 0.

Step 1: Compute inside parentheses: 4 - 3 = 1. Step 2: Multiply: 7*1 = 7.

Step 1: Use absolute value: | -12 | = 12 and | 5 | = 5. Step 2: Subtract: 12 - 5 = 7.

Step 1: Compute parentheses first: 18 - 6 = 12. Step 2: Divide: 12/3 = 4.