Unit 3: Addition & Subtraction Strategies

Here are some strategies for learning the addition facts to 18:

Adding 0 - When you add zero, you add nothing.
For example, 4+0 =4
*Online Practice*

Adding 1 (Count On) - Say the larger number and count up one number. Never recount the larger number.
For example: 5+1 =6
*Online Practice*

Adding 2 (Count Up 2) - Say the larger number and count up twice.
For example: 5+2= 7
*Online Practice*

Doubles - When you add a double, you are counting by that number once. Think of it like skip counting by that number.
For example: 5+5 = 10
*Online Practice*

Near Doubles - Add the double and then count up or count down.
For example: 5+6 (5+5+1) =11
5+4 (5+5-1) =9
*Online Practice* & Game

Commutative Property (Turn Around Facts) - The answer will be the same regardless of the order in which you add the numbers.
For example: 10+5 =15 and 5+10 =15.
*Online Practice*

Adding 10 - Think of the hundreds chart and count by ten. The ones digit stays the same and the tens digit increases by one.
For example: 4+10 = 14
*Online Practice*

Adding 9 - Add 10 and count down 1.
For example: 4+9 (4+10-1) =13
*Online Practice*

Adding 8 - Add 10 and count down 2.
For example: 4+8 (4+10-2) = 12

*Adding 5 - This strategy may be difficult to understand You can decide for yourself if it's useful.

Look for the five in both numbers and count up the extra digits.
For example: 5+7 (5+5+2) = 12

This covers most of the facts!

The leftover ones that need to be memorized are:

6+3 =9    3+6 = 9

6+4 =10   4+6 =10

7+3 =10   3+7 =10

7+4 =11    4+7+11