Number Sense and Operations Flashcards

Evaluate: 3 + 4 × 2 − 1

Answer: 10

Following order of operations (PEMDAS), multiplication is performed first: 4 × 2 = 8, then left to right: 3 + 8 − 1 = 10.

Which property is illustrated by: 5 × (3 + 4) = 5 × 3 + 5 × 4?

Answer: Distributive Property

The Distributive Property states that a(b + c) = ab + ac, which is exactly what is shown here.

What is the absolute value of −17?

Answer: 17

Absolute value represents the distance from zero on the number line, so |−17| = 17.

Which of the following is a prime number?

Answer: 53

53 is prime because it has no divisors other than 1 and itself; 51 = 3 × 17, 57 = 3 × 19, and 1 is not prime by definition.

What is the least common multiple (LCM) of 6 and 8?

Answer: 24

Since 6 = 2 × 3 and 8 = 2³, the LCM = 2³ × 3 = 24.

Evaluate: (−3) × (−4) + (−2)

Answer: 10

Two negatives multiplied give a positive: (−3) × (−4) = 12, then 12 + (−2) = 10.

What is 2⁵?

Answer: 32

2⁵ means 2 multiplied by itself 5 times: 2 × 2 × 2 × 2 × 2 = 32.

Which number is written in correct scientific notation?

Answer: 2.35 × 10⁴

Scientific notation requires the coefficient to be at least 1 and less than 10; 2.35 × 10⁴ = 23,500 and satisfies this condition.

Which of the following numbers is divisible by 9?

Answer: 432

A number is divisible by 9 if the sum of its digits is divisible by 9; for 432: 4 + 3 + 2 = 9.

What is the greatest common factor (GCF) of 36 and 48?

Answer: 12

36 = 2² × 3² and 48 = 2⁴ × 3, so GCF = 2² × 3 = 12.

What is √144?

Answer: 12

12 × 12 = 144, so the square root of 144 is 12.

Which of the following is an irrational number?

Answer: √5

√5 ≈ 2.2360679… is a non-terminating, non-repeating decimal and cannot be expressed as a fraction, making it irrational.

Which list correctly orders −3, 0.5, −1.2, and 2 from least to greatest?

Answer: −3, −1.2, 0.5, 2

On the number line, −3 < −1.2 < 0.5 < 2, so the correct order is −3, −1.2, 0.5, 2.

Round 3,847 to the nearest hundred.

Answer: 3,800

The tens digit is 4 (less than 5), so the hundreds digit stays at 8 and the number rounds down to 3,800.

What is 3/4 + 5/6?

Answer: 19/12

Converting to a common denominator of 12: 3/4 = 9/12 and 5/6 = 10/12, so 9/12 + 10/12 = 19/12.

What is 15% of 80?

Answer: 12

15% of 80 = 0.15 × 80 = 12.

The ratio of boys to girls in a class is 3:5. If there are 24 boys, how many girls are there?

Answer: 40

Since 24 boys corresponds to 3 parts, one part = 8; 5 parts (girls) = 5 × 8 = 40.

In the number 5,847,392, what is the place value of the digit 4?

Answer: Ten-thousands

Reading from right to left: ones, tens, hundreds, thousands, ten-thousands — the digit 4 sits in the ten-thousands place.

Evaluate: −8 + 15 − 3

Answer: 4

−8 + 15 = 7, then 7 − 3 = 4.

Which fraction is equivalent to 0.625?

Answer: 5/8

0.625 = 625/1000; simplifying by dividing numerator and denominator by 125 gives 5/8.