We used Singapore Math this past year for first grade. In it, we were introduced to number bonds.
Although I taught math for several years, I had never heard of number bonds before.
I found the concept interesting. Once I found a good way for my daughter to use it, her understanding of place value deepened.
The concept is:
- Take a two digit number
- Split it into the tens and ones
For example: 78=70+8
Number bonds didn’t get really useful until we started addition with double digit numbers. I think using number bonds helped her visualize the problem. She got very good at taking numbers apart, manipulating them, and putting the result back together.
Learning is more fun when it’s cute (or my kids seem to think so). I created 3 number bond mats: addition, subtraction, and one that has both.
To download them click here:
How to Use the Number Bond Mats For Addition
I used number bonds to introduce addition (and later subtraction). We started with adding numbers that were double digit, but when added together the sum was less than 100 and didn’t require “carrying”.
I also paid attention to the numbers and made sure they weren’t ones that she could add in her head.
Here is the process:
First, I created counters for the number bond mat. You could also laminate this mat and use a dry erase marker.
Next, if you have never used number bonds before, show your child how to use the mats. Practice that until you think they understand. When I did this with Ben (5) I had him practice splitting a number into tens and ones on just one flower so that I didn’t have to print another mat. The correct word for “splitting” a number is—decomposition….I know fancy words. 🙂
Give your child a problem. They may need help until they get how to use the mats. We had been using number bonds with Grace for a while so she caught on really quickly.
Let’s pretend you want to add 35+24
You can also use number bonds to add numbers that you would traditionally have to “carry” but it is a little awkward depending on the level of your student. Let’s say you want to add 35+29. You would have the same steps 1-3. On step 4 it is a little more challenging to add the two numbers together. You could split 14 into 10 + 4 if your student finds adding 50+14 too difficult. Here is how it might look:
I find using number bonds with addition really helpful. I only use it with subtraction when there is no “borrowing”. I think it looses it’s meaning after that and that there are much better ways to learn to subtract large numbers.