FAST Math Grade 4 flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Place value of a digit

The value a digit has because of its position in a number. Each place is 10 times the place to its right, so in 3,472 the 4 is worth 400.

Rounding whole numbers

Find the place being rounded, then check the digit to its right. If it is 5 or more, increase the place digit by 1; otherwise keep it.

Prime number

A whole number greater than 1 whose only factors are 1 and itself. Examples include 2, 3, 5, 7, and 11; the number 1 is not prime.

Factor versus multiple

A factor divides a number evenly, while a multiple is a product of that number and a whole number. Factors of 12 include 3; multiples of 3 include 12.

Partial products method

A multiplication strategy that splits one factor by place value. For 34 × 12, compute 34 × 10 = 340 and 34 × 2 = 68, then add to get 408.

Remainder in division

The amount left over after dividing into equal whole-number groups. It must be smaller than the divisor; 17 ÷ 5 gives 3 with remainder 2.

Order of operations

The agreed sequence for evaluating expressions: parentheses first, then multiplication and division left to right, then addition and subtraction left to right.

Equivalent fractions

Fractions that name the same amount. Multiply or divide the numerator and denominator by the same nonzero number, so 2/3 equals 8/12.

Common denominator

A shared denominator that lets you add or subtract fractions. Rewrite each fraction as an equivalent fraction with that denominator, then combine the numerators.

Comparing fractions

Rewrite fractions with a common denominator or compare each to 1/2. Since 3/5 = 6/10 and 1/2 = 5/10, 3/5 is greater.

Fraction as division

A fraction a/b means a divided by b. So 3/4 equals 3 ÷ 4 = 0.75, and 7/2 equals 7 ÷ 2 = 3.5.

Mixed number conversion

Change a mixed number to a fraction by multiplying the whole number by the denominator, adding the numerator, and keeping the denominator: 2 1/3 = 7/3.

Decimal place values

Positions to the right of the decimal point name tenths, hundredths, and thousandths. In 0.47 the 4 means 4 tenths and the 7 means 7 hundredths.

Comparing decimals

Line up decimal points and compare digits place by place from left to right. 0.45 is less than 0.5 because 45 hundredths is less than 50 hundredths.

Multiplying fraction by whole number

Multiply the numerator by the whole number and keep the denominator: 3/4 × 2 = 6/4, which simplifies to 1 1/2.

Variable

A letter or symbol that stands for an unknown or changing number. In n + 5 = 12, the variable n stands for 7.

Expression versus equation

An expression contains numbers, operations, and variables with no equals sign, such as 3x + 4. An equation states two expressions are equal, such as 3x + 4 = 10.

Evaluating an expression

Substitute the given value for each variable, then follow order of operations. For 3x + 4 with x = 2, compute 6 + 4 = 10.

Inverse operations

Operations that undo each other: addition undoes subtraction, and multiplication undoes division. They are used to solve equations and keep both sides balanced.

Solving a one-step equation

Apply the inverse operation to both sides so the variable stands alone. For x + 7 = 15, subtract 7 from both sides to get x = 8.

Pattern rule

The rule describing how a sequence changes. In 3, 7, 11, 15 the rule is add 4, so the tenth term is 3 + 9 × 4 = 39.

Input-output table

A table pairing each input with an output according to a rule. If the rule is multiply by 3, an input of 5 produces an output of 15.

Customary length units

Customary length relationships: 12 inches equal 1 foot, 3 feet equal 1 yard, and 5,280 feet equal 1 mile.

Metric prefixes

Prefixes that change a unit by powers of 10: kilo means 1,000, centi means 1/100, and milli means 1/1,000, so 1 meter = 100 centimeters.

Elapsed time

The amount of time between a start and an end time. Count forward in hours and minutes, regrouping 60 minutes as 1 hour when subtracting.

Area and perimeter formulas

For a rectangle, area equals length times width and perimeter equals 2 times the sum of length and width. Area is measured in square units.

Mean of a data set

The fair-share average found by adding all values and dividing by the number of values. The mean of 4, 6, and 8 is 18 ÷ 3 = 6.

Line plot

A number line with X marks above each value showing how often it occurs. The value with the tallest stack of marks is the most common.

Triangle angle sum

The three interior angles of any triangle add to 180°. If two angles measure 50° and 60°, the third angle measures 70°.

Parallel and perpendicular lines

Parallel lines never intersect and stay the same distance apart. Perpendicular lines intersect at exactly a 90° angle.

Classifying triangles

Triangles are named by angles (acute, right, obtuse) or by sides (equilateral, isosceles, scalene). An equilateral triangle has three equal sides and three 60° angles.

Line of symmetry

A line that divides a figure into two matching halves that fold exactly onto each other. A square has four lines of symmetry.