1. Chapter 1 Addition and Subtraction within 1,000 2012 Edition

2. The Commutative Property of Addition States that you can add two or more numbers in any order and get the same sum. 2 + 3 = 5 3 + 2 = 5 Lesson 1

3. The Identity Property of Addition states that the sum of any number and zero is that number 7 + 0 = 7 3 + 0 = 3 Lesson 1

4. pattern: a repeating or growing sequence that follows a rule rule: a procedure (usually involving arithmetic operations) to determine an “output” value from an “input” value 1, 3, 5, ___, ___, ___ The rule for the pattern is add 2 or +2 Lesson 1

5. even: a whole number that is evenly divisible by 2 odd: a whole number not evenly divisible by 2 Lesson 1

6. round: to replace a number with another number that tells about how many or how much 0 1 2 3 4 5 6 7 8 9 5 or greater go up to the next tens, hundreds or thousands. Less than 5 stay at the current tens, hundresds, or thousands. 25 rounded to the nearest 10 = 30 23 rounded to the nearest 10 + 20 Lesson 2

7. An estimate is a number close to the exact amount 29 rounded to the nearest ten is 30 179 rounded to the nearest hundred is 200 Lesson 3

8. Compatible numbers: numbers that are easy to compute mentally and are close to the real number. 425 +275 700 Lesson 3 427 + 273

9. The Associative Property of Addition states that you can group addends in different ways and still get the same sum. It is also called the Grouping Property (16 + 7) + 23 = 16 + (7 + 23) Lesson 5