FAST Math Grade 3 cheat sheet

Grade 3 Mathematics (B.E.S.T. Standards)

• Place value: in a 4-digit number, each digit is worth 10 times the digit to its right; 3,472 = 3,000 + 400 + 70 + 2 in expanded form.

• Rounding rule: to round to the nearest 10 or 100, find the target place, then look at the digit to its right; 5 or more rounds up, 4 or less stays the same.

• Multiplication is repeated addition and equal groups: 4 × 6 means 4 groups of 6, which equals 24; the answer is called the product.

• Division separates a total into equal shares: 24 ÷ 4 = 6 because 4 × 6 = 24; multiplication and division are inverse operations.

• Unknown-factor rule: 3 × ? = 21 is solved by dividing 21 ÷ 3 = 7, so a missing factor is found with division.

• Properties: commutative 3 × 8 = 8 × 3; associative (2 × 3) × 4 = 2 × (3 × 4); distributive 6 × 7 = 6 × 5 + 6 × 2.

• Fractions: a fraction a/b shows a equal parts out of b equal whole parts; the denominator b is the total number of equal parts, the numerator a is how many are counted.

• Equivalent fractions and comparison: 1/2 = 2/4 = 3/6; when denominators are equal, the fraction with the larger numerator is greater (3/8 > 2/8).

• Area and perimeter: perimeter is the distance around a figure (add all side lengths); area is the number of unit squares covering it (length × width for a rectangle).