OST Grade 4 Math flashcards

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

Multiplicative comparison

A statement comparing two quantities using 'times as many as.' For example, 8 is 4 times as many as 2 because 8 = 4 × 2.

Factor pair

Two whole numbers whose product is a given number. The factor pairs of 12 are 1×12, 2×6, and 3×4.

Prime number

A whole number greater than 1 with exactly two factors: 1 and itself. Examples are 2, 3, 5, 7, and 11.

Composite number

A whole number greater than 1 that has more than two factors. For example, 12 is composite because 1, 2, 3, 4, 6, and 12 divide it.

Remainder

The amount left over after dividing into equal whole groups. In 17 ÷ 5, the quotient is 3 and the remainder is 2, which is less than 5.

Order of operations

The rules for evaluating an expression: compute inside parentheses first, then multiply and divide left to right, then add and subtract left to right.

Multi-step word problem

A problem needing more than one operation to solve. Solve each step in order and label what each answer represents before using it again.

Place value

The value of a digit based on its position. In 6,304 the 6 means 6,000, the 3 means 300, and the 4 means 4.

Expanded form

A number written as the sum of each digit's place value. For example, 5,207 = 5,000 + 200 + 0 + 7.

Rounding to a place

Replacing a number with the nearest value of a given place. Check the digit to the right; 5 or more rounds up, 4 or less keeps the digit.

Regrouping in subtraction

Borrowing one unit from the next place to the left so a column can be subtracted. In 402 − 178, regroup 1 hundred as 10 tens, then 1 ten as 10 ones.

Partial products

The products found by multiplying each place-value part of a factor separately. For 34 × 6: 30 × 6 = 180 and 4 × 6 = 24, so the total is 204.

Multiplying by powers of ten

Multiplying by 10, 100, or 1,000 moves digits that many places left, so the product ends in that many zeros: 56 × 100 = 5,600.

Quotient and divisor

In a division sentence, the divisor is the number you divide by and the quotient is the result. In 42 ÷ 7 = 6, 7 is the divisor and 6 is the quotient.

Equivalent fractions

Fractions that name the same amount. Multiply or divide numerator and denominator by the same nonzero number: 1/2 = 2/4 = 5/10.

Comparing fractions

Deciding which fraction is greater. With the same denominator, compare numerators; with the same numerator, the smaller denominator is greater.

Benchmark fraction

A familiar fraction such as 0, 1/2, or 1 used to estimate and compare. A fraction is less than 1/2 when its numerator is less than half its denominator.

Mixed number

A whole number and a fraction written together. An improper fraction such as 9/4 equals the mixed number 2 1/4.

Adding like denominators

When denominators match, add the numerators and keep the denominator: 2/7 + 3/7 = 5/7. The denominator names the size of the parts.

Fraction of a whole number

Multiply the whole number by the numerator, then divide by the denominator. For example, 2/3 of 12 is (12 × 2) ÷ 3 = 8.

Fraction and decimal equivalence

A fraction with denominator 10 or 100 can be written as a decimal. For example, 3/10 = 0.3 and 45/100 = 0.45.

Area of a rectangle

Multiply length by width. A rectangle 7 units long and 4 units wide has an area of 28 square units.

Perimeter of a rectangle

Add all four side lengths, or compute 2 × (length + width). A 6-by-3 rectangle has perimeter 18 units.

Elapsed time

The amount of time between a start and an end time. Subtract the start time from the end time, regrouping 1 hour as 60 minutes if needed.

Line plot

A number line with an X above each data value. The value with the most X's is the most common, and the spread shows the range.

Customary length units

1 foot = 12 inches, 1 yard = 3 feet, and 1 mile = 5,280 feet. To convert feet to inches, multiply by 12.

Metric mass and capacity

1 kilogram = 1,000 grams, 1 liter = 1,000 milliliters, and 1 meter = 100 centimeters. Multiply to convert to a smaller unit.

Right angle

An angle that measures exactly 90 degrees, often marked with a small square. Perpendicular lines meet to form right angles.

Parallel lines

Lines in the same plane that never intersect and stay the same distance apart, such as the two long sides of a rectangle.

Line of symmetry

A line that folds a figure onto itself so the two halves match exactly. A square has 4 and a rectangle has 2.

Trapezoid

A quadrilateral with exactly one pair of parallel sides. The parallel sides are called bases and the other two are the legs.

Additive angle measure

When an angle is split into parts, the whole angle equals the sum of the parts. A 100° angle split into 30° and 70° shows this.