Addition within 20

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Addition is the mathematical operation of combining two or more numbers to get a total.

The commutative property states that changing the order of the addends does not change the sum (e.g., a + b = b + a).

The associative property states that the way in which numbers are grouped in addition does not change the sum (e.g., (a + b) + c = a + (b + c)).

A number line is a visual representation of numbers on a straight line, used to illustrate addition by showing the movement from one number to another.

You can use physical objects like blocks or counters to visually represent the addition of two groups.