Video Transcript
We can think about place value to help us subtract. Pick the correct way to decompose 35 into 10s and ones. Subtract 18 from 35 by following these steps. Regroup one 10 into 10 ones. Take away eight ones. Take away one 10. 35 take away 18 equals what?
In this question, we need to think about place value. We’re asked to decompose the number 35 into 10s and ones. And we’re given four possible answers. We can partition the number 35 into 10s and ones. The five is worth five ones, and the three in 35 is worth three 10s, or 30. So, we’re looking for the place value chart which shows us three 10s and five ones. The first of our four models shows three 10s and five ones. So, this is the correct way to decompose 35 into 10s and ones.
Next, we have to subtract 18 from 35. And we’re told to follow these steps. First, regroup one 10 into 10 ones. This step has already been done for us. There were three 10s in 35, and one 10 has been taken away. Now, there are two 10s. This 10 has been exchanged for 10 ones. We took one 10 and exchanged it for 10 ones. We did have five ones in 35. Now, we have 15 ones. Next, we’re asked to take away the eight ones. What is 15 take away eight? The answer is seven. Finally, we have to take away one 10. Two take away one equals one. 35 take away 18 equals 17.
We thought about place value to help us subtract. We picked the correct way to decompose 35 into 10s and ones. The first-place value chart shows three 10s and five ones. Then, we subtracted 18 from 35 by following the steps. First, we regrouped one 10 into 10 ones. Then, we took away eight ones and one 10 to give us our answer of 17. 35 take away 18 equals 17.