Mental Math Strategies
We are working on mental math strategies* to help with our addition and subtraction facts. The goal is to practice these strategies until the answers become second nature. .
*Of course, if students have already mastered their facts, they won't need to go through this mental math strategy process because the facts have already been stored in long-term memory. :)
Addition
*Of course, if students have already mastered their facts, they won't need to go through this mental math strategy process because the facts have already been stored in long-term memory. :)
Addition
- Counting On (8+3= ? Think 8...9, 10, 11)- Most efficient when equation has 1, 2, 3, or 4
- Doubles (4+4=8)- memorized
- Thinking of Doubles (3+5= ? Think: 4+4=8, so 3+5 = 8)
- Doubles +1 (3+4= ? Think 3+3=6, so 1 more is 7)
- Counting Back (8-3= ? Think 8...7, 6, 5)- Most efficient when equation -1, -2, -3, or -4)
- Using Doubles (8-4= ? Think 8 is double of 4, so 8-4=4.)
- Building on Doubles (9-4= ? Think 9 is a doubles +1 fact (9= 4+4+1=4+5), so the difference is 5)
Addition Facts
All 121 addition facts below can be easily memorized with the following FIVE mental math strategies! (Once mastered, students should also be able to rapidly recall the related subtraction facts.)
There are other ways to memorize these addition facts, but these are five common ones. NOTE: I allow students to use whatever strategy is most efficient for them. This table is just a sample.