For those of you who don't know counting, just memorize these numbers in this particular order: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12...

Those are known as the

**counting**numbers. (If you're a mathematics major, you might better know them as the

*natural numbers*.)

Now, let's add by 1.

1 + 1 = 2

2 + 1 = 3

3 + 1 = 4

4 + 1 = 5

5 + 1 = 6

6 + 1 = 7

7 + 1 = 8

8 + 1 = 9

9 + 1 = 10

Simple? See if you can memorize it. Better yet, see if you can find an alternative to memorization. You should know that if 1 is added to a number then the result is the next counting number.

**A general pattern: (counting number) + 1 = (next counting number)**

So if 13 is the next counting number after 12, then 12 + 1 = 13

Let's take the number 6.

6 + 1 = 7

We can reverse the order the numbers are added and still get the same result.

6 + 1 = 7

1 + 6 = 7

6 + 1 is the same thing as 1 + 6.

Let's do a quick review of the counting numbers: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 and so on...

1 and 6 are known as

**addends**and the number 7 is known as the

**sum**.

**A general pattern: addend + addend = sum**

If you're starting to think of mathematics as a bunch of general patterns, then you're already thinking like a mathematician.

But the general pattern can be put into a more general pattern.

**Sum = addend + addend**

Let's say with the numbers 6, 1, and 7, we can formulate four equations.

6 + 1 = 7

1 + 6 = 7

7 = 1 + 6

7 = 6 + 1

Let's take another case, say 3, 1, and 4.

3 + 1 = 4

1 + 3 = 4

4 = 1 + 3

4 = 3 + 1

Got it? Good. Now make equations out of these numbers.

Problem 1: 1, 2, and 3

Problem 2: 6, 1, and 7 (already done)

Problem 3: 8, 1, and 9

Problem 4: 9, 1, and 10

Problem 5: 10, 1, and 9 (see problem 4 but re-do it)

Problem 6: 11, 12, and 1

Problem 7: 10, 1, and 11

Problem 8: 88, 89, and 1

Problem 9: 1, 100, and 99

Problem 10: 566, 1, and 567

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