Chapter 1 Addition and Subtraction within 1, Edition

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

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

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

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

round: to replace a number with another number that tells about how many or how much 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 = rounded to the nearest Lesson 2

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

Compatible numbers: numbers that are easy to compute mentally and are close to the real number Lesson

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