Hi. In this education post, I want to cover the topic of doubles as adding by itself.
Topics
- Twice = Double = Add By Itself
- Extension - Triple As In Add The Number Three Times
- Extension - Multiply By Four = Quadruple = Double The Double
- A Flashcard Activity For Doubles
Twice = Double = Add By Itself
For young students, a way to introduce them to multiplication is through repeated addition. Instead of having them do twice a number or doubling through multiplication, you can tell them to add the numbers by itself. Double of 5 would be 5 + 5 = 10. Double of 8 would be 8 + 8 = 16.
Doubling larger numbers would be tougher without a calculator. For something like twice of 157, I would separate 157 into 150 + 7 first. Take double of 150 which is 300 and take double of 7 which is 14. Add the double results of 300 and 14 together to get the double of 157 which 314.
Extension - Triple As In Add The Number Three Times
Once the concept of doubles is mastered, a natural extension would be do triples. Double a number involves a number plus itself. Tripling a number is just adding by itself twice.
Triple of 10 would be 10 + 10 + 10. The number ten appears three times.
Finding the triple of a larger number such as 147 would be tricky as it would be 147 + 147 + 147. I would do the double first which would be 147 + 147 which equals to 294. After obtaining the 294, add the 147 to obtain 341.
Extension - Multiply By Four = Quadruple = Double The Double
Multiplying by four sounds scary for young students but you can use a strategy where multiplying by four is viewed as double the double. Four times a number is doubling the number first and then doubling that double.
Four times seven can be viewed as taking double of seven which is 14. The number 14 would be doubled again to obtain 28.
A tougher example would be 177 times four. Double of 177 would be 354 which is not that easy to compute mentally and fast. The double of 354 would be 708. The answer to 177 x 4 = 708.
A Flashcard Activity For Doubles
I think one of the best ways to get young students engaged and learning is through the use of flashcards. They are simple to use, fast and is good at testing the student's recall abilities.
For the doubles flashcard activity, you can use a deck of cards. Face cards would count as ten and aces would be ones. You can also combine cards to create two digit or three digit numbers. Having two cards that say 2 and 7 could represent 27 for example. Show the student a card at random and quiz them on what the double of the number is. For example, if the student is shown a random card that is an eight, ask what the double of eight is.
This flashcards activity can also be used for triples, quadruples and half of a number. Finding half of a number is the reverse of finding doubles.
