Hi there. In this elementary math education post, I talk about a strategy and memory aid suitable for young children from grades 1 to 2. It is called Friends Of Ten. The idea came from a fellow instructor at my Mathnasium work. This concept, strategy and game is good for building memory when it comes to adding two numbers that make ten.
I did not post this through StemGeeks as I do think this is more of an education post than a mathematics post.
Ten Is Common
The number ten is a nice number to work with as it does show up often. Examples include 10% sales, ten millimetres being equal to one centimetre, ten years is one decade, and multiplying by ten involves adding a zero. Scientific notation also expresses numbers in terms of power of ten with a positive exponent for large numbers and negative exponents for really small numbers.
Friends Of Ten
The idea behind friends of ten is to find two numbers that add together to make 10. One example would be three and seven being friends as 3 + 7 = 10. Another example would be 1 and 9. I have included a full table below for the friends of ten.
| First Number | Second Number |
|---|---|
| 0 | 10 |
| 1 | 9 |
| 2 | 8 |
| 3 | 7 |
| 4 | 6 |
| 5 | 5 |
| 6 | 4 |
| 7 | 3 |
| 8 | 2 |
| 9 | 1 |
| 10 | 0 |
Knowing the number pairs that make ten is also useful for adding numbers that end up not being equal to ten. The numbers 7 and 5 are not friends of ten so you know for sure that 7 + 5 is not equal to ten. A friend of 7 that makes ten would be 3. Five is two greater than three so 7 + 5 would be two greater than ten which would be 12.
A Flashcard Game With Friends of Ten
This friends of ten idea can be taught with the use of deck of cards. Face cards would count as 10 and aces would be ones. You can show a random card and ask the student what is a friend of the number value shown on the card. As an example, if the random card shows up as a 2 you can ask the student what is a friend of 2 that makes 10. The answer here is 8. I do like flashcards in general as it builds memory and speed.
