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Topic 2 Grade 3 Math

Number Sense: Addition & Subtraction

addends numbers added together to give a sum
sum the answer to an addition problem
commutative (order) property of addition numbers can be added in any order and the sum will be the same; example: 2 + 3 = 3 + 2
associative (grouping) property of addition the grouping of addends can be changed and the sum will be the same; example: (2 + 3) + 1 = 2 + (3 + 1)
identity (zero) property of addition the sum of any number and zero is that number; example: 2 + 0 = 2
fact family a group of related facts using the same numbers; example: 2 + 3 = 5, 3 + 2 = 5, 5 - 3 = 2, 5 - 2 = 3
difference the answer to a subtraction problem
round to replace a number with a number that tells about how much or about how many to the nearest ten, hundred,thousand, and so on
estimate to give an approximate number or answer
compatible numbers numbers that are easy to add, subtract, multiply, or divide mentally
equation a number sentence that uses = (is equal to)
reasonable answer an answer that makes sense
Created by: pdeprosse