Subtracting Ones from Teen Numbers
In this video, we will learn how to subtract a one-digit number from a teen number. We can make teen numbers from a 10 and some ones. 11 is a teen number. We can break this number apart into a 10 and one one. 10 and one makes 11. We could make the number 19 from a 10 and nine ones. In this video, we’re going to learn how to take away ones from a teen number. 19 is a teen number, and teen numbers have two digits. They have a tens digit and a ones digit.
The number six only has one digit. This digit is its ones. So we’re going to be taking away ones from a two digit-number which has tens and ones. So we’re going to be taking away from the ones digit. To take away six from 19, we need to take away six ones. One, two, three, four, five, six. Did you notice how the ones were decreasing? We had nine ones. We took away six. Now we have three ones left. 10 and three ones is 13. So 19 take away six equals 13. Let’s try some practice questions.
Daniel drew this model to help him subtract. Which of these has the same answer as 16 take away five? Is it 10 plus one, 10 plus five, or one plus one? What is 16 take away five?
Daniel is trying to find the answer to 16 take away five. He’s used ten frames to make a model of the number 16 using a 10 and six ones. He’s taken away five of his ones, which leaves him with 10 and one. 10 and one makes 11. We’ve answered the first part of the question. Daniel’s model shows 10 plus one. 10 plus one gives us the same answer as 16 take away five. We know that 10 plus one is 11, so 16 take away five is 11.
What is 13 take away three?
Let’s look closely at the model which has been drawn to help us. 13 is a teen number; it’s made from a 10 and three ones. 10 and three makes 13. We’re taking a one-digit number, number three, away from a two-digit number, number 13. And the model is telling us to take away the ones first. There are three ones in 13, and we have to take away three ones. What is three take away three?
If we take away our three counters, which represent our three ones, we have no ones left. Three take away three equals zero. Now, we’re left with a 10 and no ones. 10 plus zero is 10. So 13 take away three equals 10.
Fill in the blank. 16 take away four equals what.
The number 16 is a two-digit number. We can break it apart into 10 and six ones. We have to take away four. Four is a one-digit number. Its digit represents the number of ones it has. So we just need to take away four ones from our six ones. Now, we have a 10 and two ones. 10 and two is 12. 16 take away four equals 12. The missing number is number 12.
What have we learned in this video? We’ve learned that when we subtract a one-digit number from a teen number, we can break the teen number apart into tens and ones and then subtract the ones.