Number and the Number System

What is the value of the digit 7 in the number 47,325?

• A7
• B70
• C700
• D7,000✓

Answer: The 7 is in the thousands place, so its value is 7 × 1,000 = 7,000.

Round 38.67 to the nearest whole number.

• A38.5
• B40
• C39✓
• D38

Answer: The decimal part is 0.67, which is greater than 0.5, so round up to 39.

Which of the following is the smallest? -5, -2, 0, 3

• A-5✓
• B-2
• C0
• D3

Answer: -5 is the smallest because it is furthest to the left on a number line.

What is 156 + 347?

• A503✓
• B512
• C489
• D403

Answer: 156 + 347 = 503. Line up the digits and add: 6+7=13 (write 3, carry 1), 5+4+1=10 (write 0, carry 1), 1+3+1=5.

What is 725 - 287?

• A448
• B512
• C412
• D438✓

Answer: 725 - 287 = 438. Subtract: 5-7 (borrow, so 15-7=8), 1-8 (borrow, so 11-8=3), 6-2=4.

What is 23 × 4?

• A92✓
• B102
• C82
• D84

Answer: 23 × 4 = (20 × 4) + (3 × 4) = 80 + 12 = 92.

What is 84 ÷ 7?

• A10
• B11
• C12✓
• D13

Answer: 84 ÷ 7 = 12, because 7 × 12 = 84.

Round 2,456 to the nearest 100.

• A2,500✓
• B2,450
• C2,400
• D2,460

Answer: Look at the tens digit (5). Since it is 5 or more, round up. 2,456 rounds to 2,500.

What is the place value of 3 in 5.03?

• AHundredths✓
• BTenths
• CThousandths
• DUnits

Answer: The 3 is two places after the decimal point, so it is in the hundredths place.

Order these numbers from smallest to largest: 2.5, 2.05, 2.55, 2.15

• A2.05, 2.15, 2.5, 2.55✓
• B2.05, 2.5, 2.15, 2.55
• C2.15, 2.05, 2.5, 2.55
• D2.55, 2.5, 2.15, 2.05

Answer: Write each one with two decimal places: 2.50, 2.05, 2.55, 2.15. Comparing them gives 2.05, 2.15, 2.50, 2.55.

What is -3 + 8?

• A-11
• B-5
• C11
• D5✓

Answer: Starting at -3 on a number line, move 8 places to the right: -3 + 8 = 5.

What is 5 - (-2)?

• A-3
• B-7
• C3
• D7✓

Answer: Subtracting a negative is the same as adding: 5 - (-2) = 5 + 2 = 7.

What is 6 × (-3)?

• A-3
• B-18✓
• C18
• D3

Answer: A positive number multiplied by a negative number gives a negative result: 6 × (-3) = -18.

What is (-12) ÷ (-3)?

• A-15
• B15
• C-4
• D4✓

Answer: A negative divided by a negative gives a positive: (-12) ÷ (-3) = 4.

Round 0.456 to 1 decimal place.

• A0.4
• B0.45
• C0.5✓
• D0.46

Answer: Look at the second decimal place (5). Since it is 5 or more, round up: 0.456 rounds to 0.5.

What is 100 ÷ 4?

• A20
• B25✓
• C30
• D40

Answer: 100 ÷ 4 = 25, because 4 × 25 = 100.

What is 15 × 12?

• A160
• B170
• C180✓
• D190

Answer: 15 × 12 = (15 × 10) + (15 × 2) = 150 + 30 = 180.

What is 1,200 ÷ 30?

• A60
• B50
• C35
• D40✓

Answer: 1,200 ÷ 30 = 40, because 30 × 40 = 1,200.

Round 12.345 to 2 decimal places.

• A12.3
• B12.34
• C12.35✓
• D12.4

Answer: Look at the third decimal place (5). Since it is 5 or more, round up: 12.345 rounds to 12.35.

What is 250 ÷ 5?

• A50✓
• B45
• C55
• D40

Answer: 250 ÷ 5 = 50, because 5 × 50 = 250.

What is 7 × 8 × 2?

• A112✓
• B140
• C98
• D56

Answer: 7 × 8 × 2 = (7 × 8) × 2 = 56 × 2 = 112.

What is 999 + 1?

• A998
• B1,000✓
• C900
• D1,001

Answer: 999 + 1 = 1,000.

What is the value of 3²?

• A9✓
• B6
• C12
• D3

Answer: 3² means 3 × 3 = 9.

What is the value of √25?

• A6
• B5✓
• C4
• D12.5

Answer: √25 = 5, because 5 × 5 = 25.

What is 2³?

• A8✓
• B16
• C4
• D6

Answer: 2³ = 2 × 2 × 2 = 8.

What is 50 × 20?

• A1,100
• B900
• C800
• D1,000✓

Answer: 50 × 20 = 1,000.

What is 144 ÷ 12?

• A10
• B11
• C12✓
• D13

Answer: 144 ÷ 12 = 12, because 12 × 12 = 144.

Estimate 48 × 21 by rounding to the nearest 10.

• A1,000✓
• B1,200
• C800
• D900

Answer: 48 rounds to 50, 21 rounds to 20. So 50 × 20 = 1,000.

What is -5 - 3?

• A-8✓
• B2
• C-2
• D8

Answer: When subtracting from a negative number, move further left on the number line: -5 - 3 = -8.

What is √36?

• A4
• B18
• C6✓
• D8

Answer: √36 = 6, because 6 × 6 = 36.