NBT Mathematics: Number Sense and Calculations Flashcards

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

Answer: 42

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

Express 4.5 × 10⁻³ in standard notation.

Answer: 0.0045

Moving the decimal 3 places left gives 0.0045.

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

Answer: p is odd

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

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

Answer: 3½ cups

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

Which of the following has the greatest value?

Answer: 0.67

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.

The product of two consecutive even integers is 168. What is the smaller integer?

Answer: 12

12 × 14 = 168, so the smaller consecutive even integer is 12.

What is 15% of 15% of 400?

Answer: 9

15% of 400 = 60, then 15% of 60 = 9.