Find Missing Number Addition Worksheets
How Find Missing Numbers, in Addition, Leads to Algebraic Thinking for Students (i.e. 46 + _7 = 73)? How many times have you been asked in your academic life to find the value of x? If your answer isn't "a lot" then maybe you're skipping school too much. What we are trying to tell you is that finding the value of missing variables is what mathematics is based on. Once you have learned basic operations of arithmetic like addition and subtraction, the complexity then is increased. In the next level, you are asked to get the value of a missing number, and its results are shown to help the process. For example, 46 + _9 = 73. This is a fairly simple equation where all you have been asked is what number needs to be multiplied with 9 and then summed with 46 to get the number 73. What we do here is take every number which is on the left side of the equation to the right and leave the unknown entity on the left. X = (73 – 46) / 9, X = 3.

Intermediate Lesson
Introduction to basic algebra with the use of reverse arithmetic.
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Independent Practice 1
Contains 18 missing numbers addition problems. The answers can be found below.
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Independent Practice 2
Contains 18 missing numbers addition problems. The answers can be found below.
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Homework Worksheet
Contains 18 missing numbers addition problems. A complete example is provided.
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Basic Rules
One of the basic rules of addition is that the order in which we add does not make a difference in the answer. If you add 6+7 and get 13, then you know that 7+6 also equals 13. This is called the commutative property of addition.