Numerical Expressions and Patterns Flashcards

Grade 5 · Math · Flashcards

Review key concepts for evaluating expressions and analyzing number patterns.

Flashcards

Numerical expression: A math phrase using numbers and operations with no equals sign; example: 4 x (3 + 2)
Evaluate: Find the value of an expression by applying the order of operations
PEMDAS order of operations: Parentheses → Exponents → Multiply/Divide (left to right) → Add/Subtract (left to right)
Effect of parentheses: Parentheses change the order operations are performed; always evaluate inside parentheses first
Evaluate: 10 - 2 x 3: 4; multiply first: 2 x 3 = 6, then subtract: 10 - 6 = 4
Evaluate: (10 - 2) x 3: 24; parentheses first: 10 - 2 = 8, then multiply: 8 x 3 = 24
Number pattern: A sequence of numbers that changes according to a rule; example: 4, 7, 10, 13 (add 3 each time)
Finding a pattern rule: Check how each term changes: subtract consecutive terms to check for addition rule; divide for multiplication rule
Pattern: 2, 6, 18, 54 — rule?: Multiply by 3 each time
Pattern: 400, 200, 100, 50 — rule?: Divide by 2 (or multiply by 1/2) each time
Writing 'six less than twice a number n': 2 x n - 6 (or 2n - 6); translate words to symbols step by step
Why does order of operations matter?: Without agreed-upon rules, 2 + 3 x 4 could equal 20 or 14 depending on which step you do first; PEMDAS ensures everyone gets the same answer
Evaluate: 4 + (12 ÷ 3) - 1: 7; parentheses first: 12 ÷ 3 = 4, then left to right: 4 + 4 - 1 = 7