Learning the addition facts is a large part of first grade math. In kindergarten, students form an understanding of what addition is through hands-on explorations, real-world examples and classroom discussion.
In first grade, they're introduced to mental math strategies to help them move beyond counting each object in a group. They no longer need to physically count something or use manipulatives to add. The strategies help them gain automaticity when answering the basic math facts.
Concepts of tens, rearranging addends, and number relationships are all instrumental in building mental math strategies and, consequently, number sense.
The Mental Math Strategies for the Addition Facts
When we teach mental math strategies for addition, we build upon what is already known. We teach the making 10 strategy first because students are already familiar with tens frames and adding 2 numbers together to make 10. It's also a strategy that will help them answer their adding 8 or 9 facts.
By connecting new facts to previously learned facts, students are better able to develop mastery of the addition facts.
Teaching the Strategies and Making it Fun
Introduce the mental math strategies using a sequenced approach that builds upon previously learned strategies, then give your students plenty of practice opportunities to help them apply the strategies.
To help you help your students practice the addition mental math strategies, I've put together a pack of games, addition strategy placements, addition strategies foldable, and an anchor chart, all with the strategies you need to help your students gain fact fluency and have fun doing it.
So what order should we teach the facts in?
Start with making 10.
Kids have already had lots of practice adding two numbers to make a ten in kindergarten. They already understand tens frames, so making a 10 is a good introduction to the strategies.
Addition facts for ten are known by different names – rainbow facts, partners of ten, or friends of ten. No matter the name, they’re a prerequisite for adding 8 and 9 and for gaining an understanding of friendly numbers which can be used later when adding two digit numbers.
0 + 10, 1 + 9, 2 + 8, 3 + 7, 4 + 6, 5 + 5 and their commutative property equations (3 + 7 becomes 7 + 3) are all addition facts for 10.
Counting on 1, 2 or 3
To count on, students put the larger number in their heads and count on the next 1, 2 or 3 numbers. This is a big step from counting the first group of objects and then counting on the second.
Understanding the commutative property is essential when teaching counting on. If kids don't understand it, you'll find they count on from the first number in the number fact regardless of whether it's the largest. This won't lead to fluency.
Adding zero to a number can be a confusing concept to comprehend so practice is needed. Students need to understand when zero is added to a number, the number remains the same. 7 + 0 = 7.
Doubles means simply doubling a number – 1 + 1, 2 + 2, 3 + 3, etc. Use visuals or pictures as a memory trigger. A great example is two hands, five fingers on one hand, five on the other – 5 + 5 = 10.
To use the doubles mental math strategy with games, use the visual strategy card included to help with recall. Make your students accountable during the game and have them write down the facts they know, the facts they need to know and how they feel about their doubles facts.
Near Doubles – Doubles + 1 more
Once students master the doubles strategy, it’s time to progress onto doubles plus one more. Grab two games to help your students apply the strategy.
To identify doubles + 1 facts, look for addends that are next to each other on the number line – 8 + 9 ( 8, 9 ). To solve this addition fact, we double the smallest number and add one more. For example, when we add 8 + 9, we double the 8 and adding one (8 + 8 + 1 = 17).
Near Doubles – Doubles + 2 More
The next strategy to teach is doubles + 2.
There are two strategies we can use for doubles + 2. For our first strategy, we get the answer by doubling the smallest number and adding two more (6 + 6 + 2 = 14), hence the name doubles + 2.
Another strategy is to double the missing number. If we look at 6 + 8, 7 is the missing number if this were a counting in ones pattern (6, _, 8).
It's easy to show the strategies with blocks. Have your students make one tower of 6 and another of 8. When placed side by side they can see they have double 6 and 2 blocks extra. They can also see when they take one block away from the tower of 8 and place it on 6 they now have 7 + 7.
If children are familiar with their teen numbers, adding 10 is easy. Use place value blocks to help them see that 17 = 1 ten and 7 ones, therefore 10 + 7 = 17. Using two tens frames is another option.
Make a 10 – Adding 9
Using tens frames and counters will also make the adding 9 strategy easier to understand. If students are answering 9 + 3, for example, use counters to display the 9 on one tens board and the 3 on the other tens board. Show how we can move one counter from the 3 board to fill out the ten which changes the equation from 9 + 3 to 10 + 2.
This strategy is easily mastered since students have already practiced adding 10.
Make a 10 – Adding 8
After the above strategies have been taught, the only number facts left to learn are 8 + 4, 8 + 5 and 7 + 4.
Use tens frame again to show how we can make a ten to add and then practice the strategy with games.
Grab a Pack Today
My addition pack contains all the above activities for each of the addition strategies mentioned.
Grab a pack of addition strategy activities from my Teachers Pay Teachers store today or join the Teaching Trove crew at the bottom of the post and grab this and three other number fact fluency packs for just $10.