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6A Unit 1
Unit 1 Vocabulary
Term | Definition | Example |
---|---|---|
Standard Form | A number written using digits and place value is in _________. | 2,174 |
The "Associative Laws" say: | * It doesn't matter how you group the numbers when you add. * It doesn't matter how you group the numbers when you multiply. (In other words it doesn't matter which you calculate first.) | Example addition: (6 + 3) + 4 = 6 + (3 + 4) Because 9 + 4 = 6 + 7 = 13 Example multiplication: (2 × 4) × 3 = 2 × (4 × 3) 8 × 3 = 2 × 12 = 24 |
Compatible numbers | are numbers that are easy to compute mentally. They are particularly useful for estimating products and quotients. | Estimate 151 ÷ 146 151 ≈ 150, 14.6 ≈ 15 150 ÷ 15 = 10 151 ÷ 14.6 ≈ 10 |
Expanded Form | is a sum that shows the place and value of each digit of a number. | 0.75 = 0.7 + 0.05 |
Expression | is a mathematical phrase that contains numbers and operation symbols. | 18+11×6 |
Front-end estimation | First adding the "front-end" digits. Then you estimate the sum of the remaining digits. You adjust the sum of the front-end digits if necessary. | Estimate $3.09 + $2.99 $3.09 $ .09 +$2.99 $ .99 $5 about $1 So $3.09 + $2.99 ≈ 5 + 1, or $6 |
Order of operations | Parenthesis Exponents Multiplication Division Addition Subtraction | 23(7-4) = 23 3 = 8 3 = = 24 |
Commutative Property of Addition | Changing the order of the addends does not change the sum. | 9+5 = 5+9 |
Identity Property of Addition | The sum of 0 and any number is that number. | 0+9=9 |