Equality is a relationship in which both sides represent the same quantity, so an addition equation is true only when its two sides have equal values—not because the expression after the equal sign is simply “the answer.” Learners determine missing addends or totals and make simple equations true, including forms such as , , or , with whole numbers and sums within 20; more general variables, larger numbers, and multi-step equations are not included.
An equation is true when both sides have the same value. The equal sign means “is the same as.”
Look at this equation:
The missing number tells how many more we need to add to to make .
Start at and count up to :
That is numbers, so the missing addend is .
Write it in the equation:
Check both sides: is , and the other side is . The two sides are equal, so the equation is true.
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