Place Value

Unit Review Sheet

Facts and Definitions

Lesson 1: Numbers to 1,000,000 Review

• A factor is a number that is multiplied by another number to get a product.
• A multiple is the product of a number and another number.
• A prime number is a number greater than 1 that has only 2 factors, the number itself and 1 (such as 2, 3, 11).
• A composite number is a number that has more than 2 factors (such as 4, 6, 12).
• The number 1 is neither prime nor composite.
• The only even prime number is 2. All other even numbers have 2 as a factor.
• Expanded form expresses a number by showing the value of each digit. In expanded form, 4,532 is 4,000 + 500 + 30 + 2.
• Expanded notation, or super expanded form, expresses a number by showing each digit multiplied by its place value. In expanded notation, 4,532 is (4 × 1,000) + (5 × 100) + (3 × 10) + (2 × 1).

Lesson 2: Comparing and Ordering Numbers

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Lesson 3: Digits to the Left and Right

• Decimal number: a number that has a decimal point
• Decimal point: the most important part of a decimal number that shows where numbers begin getting larger than 1 (to the left of the decimal point) and where they begin getting smaller than 1 (to the right of the decimal point)
• The digits to the left of the decimal point are whole numbers.
• The digit to the right of a decimal point is in the tenths place, and the digit to the right of the tenths place is in the hundredths place.
• A digit in one place represents 10 times as much as it represents in the place to its right and 1/10 of what it represents in the place to its left.

Lesson 4: Decimals to Thousandths

• Thousandths: decimal place to the right of the hundredths place, the third place to the right of the decimal point
• Decimal numbers can be written using expanded form. For example, 0.25 in fraction expanded form is 2/10 + 5/100. In decimal expanded form, it is 0.2 + 0.05.
• Decimal numbers can be written using expanded notation (in which the digit in each place is multiplied by its place value).
• In fraction expanded notation, 0.25 is (2 × 1/10) + (5 × 1/100).
• In decimal expanded notation, 0.25 is (2 × 0.1) + (5 × 0.01).

Lesson 5: Comparing Decimals

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Lesson 6: Rounding to Thousandths

• Round to the greatest place means rounding to the highest place value showing.
• Round to the nearest whole number means rounding to the ones place.

Lesson 7: Powers of 10

• Powers of 10: numbers made by multiplying 10 by itself (for example, 10 × 10 × 10 = 1,000)

Lesson 8: Working With Powers of 10

• Exponent: a number written to the right and slightly above a base number that shows how many times to multiply the base number by itself (for example, 10²= 10 × 10)
• Scientific notation is a method of writing very large numbers.
• To multiply by powers of 10, you either move the digits to the left or the decimal point to the right.
• To divide by powers of 10, you either move the digits to the right or the decimal point to the left.

Lesson 9: Roman Numerals

• Roman numerals: the number system developed by the ancient Romans, still used today on clocks, to name sporting events, to name rulers of countries, in books, and in a variety of other places

Lesson 10: Problem Solving

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Lesson 11: Unit Test

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Final Project: Number Trading Cards

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