NBT NBT Mathematics: Number Sense and Calculations 5

Question 1

What is the greatest common factor (GCF) of 84 and 126?

Accepted Answer

42

Answer

84 = 2² × 3 × 7 and 126 = 2 × 3² × 7, so GCF = 2 × 3 × 7 = 42.

Question 2

Express 4.5 × 10⁻³ in standard notation.

Accepted Answer

0.0045

Answer

Moving the decimal 3 places left gives 0.0045.

Question 3

If p is a prime number greater than 2, which statement is always true?

Accepted Answer

p is odd

Answer

All prime numbers greater than 2 are odd, since any even number greater than 2 is divisible by 2.

Question 4

A recipe uses 2⅓ cups of flour. If you want to make 1½ times the recipe, how many cups of flour do you need?

Accepted Answer

3½ cups

Answer

2⅓ × 1½ = (7/3) × (3/2) = 21/6 = 7/2 = 3½ cups.

Question 5

Which of the following has the greatest value?

Accepted Answer

0.67

Answer

0.67 is slightly greater than 2/3 ≈ 0.6667; 67% = 0.67 = 0.67 exactly, and 0.6̄ = 2/3, so 0.67 and 67% are equal and greatest.

(NBT) National Benchmark Test Practice Test