Addition Math Strategies

By Cindy Vaske

Addition Math Strategies

Zero Facts:  When there is a zero.  The answer is the other number.  Some kids need to cross out the zero to help them think through the process.  

Doubles:  When both numbers (addends) are the same.  To help memorize them we used props to go with each number sentence:          

                                         1+1 = 2 as a pair of shoes.

                                         2+2 = 4 as the tires of a car.

                                         3+3 = 6 as six pack of soda.

                                         4+4 = 8 as legs on a spider.

                                         5+5 = 10 as all your fingers on both hands.  

                                         6+6 = 12 as a dozen eggs.

                                         7+7 = 14 as two weeks. 

                                         8+8 = 16 as a small box of crayons.

                                         9+9 = 18 as a double 9 domino. 

Count-On's:  When there is a 1, 2, or a 3.  You put the appropriate number of dots on the 1, 2, or 3 you find in the number sentence.  Then start counting by saying the larger number first and counting on the touch point dots of the other number.  Sometimes 4 is also considered a count on.  

Magic Nines: When there is a 9.  The story goes, "The  9 really wants to be a 10, so you put a one (in the tens place).  So, his buddy (the other addend/number) gives him one so he is now (a number smaller)."  9+7 = 16 (since 7 gave up one for 9, so the 9 can be a 10, the 7 is now a 6).  

Sharing: You need to count, starting at the smaller number (addend), going to the larger number (addend).  If you stop in the middle, it is a sharing problem ( they are sharing the number between them).  You double the number they are sharing (the number in the middle)and that is your answer.  You can also use a number line.  Put a finger on each number so you can see which number they are sharing.  Example:  7+5.  They share 6.  You double the 6 and the answer is 12.  

Doubles +1:  You need to count, staring at the smaller number (addend), going to the larger number (addend).  If you don't stop in the middle, you go straight to the larger number, then you use the Doubles +1 strategy.  You can also use a number line.  Put a finger on each number so you can see that they are next door to each other.  Once you know it's a doubles+1 you do what the strategy tells you to do.  Double the lower number and add 1 more (take one off the higher number to make it into a doubles problem and then add the one back in).  Example:  6+7.  Six is lower than seven so you double  the six to make 12.  Add one more and you have your answer.    

Chant: If you have 5+8 or 8+5.  You do a rhythm and the answer is 13.