Question Video: Subtracting Two-Digit Numbers from Two-Digit Numbers without Regrouping Mathematics • 1st Grade

Video Transcript

We can think about place value to help us subtract. Pick the correct way to decompose 58 into tens and ones. Subtract 26 from 58 by taking away six ones and then two 10s.

In this question, we have to subtract 26 from 58. And we’ve been given some models to help us. When we’re subtracting a two-digit number like 26 from another two-digit number like 58, it helps if we start by modeling the number we’re taking away from. In this case, we need to model the number 58. Only one of our models is correct. How could we decompose or break apart the number 58 into tens and ones correctly? It must be the second model. It has a five in the tens place and an eight in the ones place. The model shows five 10s, 10, 20, 30, 40, 50, and eight ones. So this is the correct way to decompose 58 into tens and ones.

We can also use this model to help us subtract. We’ve modeled the number we’re taking away from, which is 58. Now we can subtract 26. We always start by subtracting the ones first. We have eight ones in the number 58, and we need to subtract six. Eight ones take away six ones leaves us with two ones. Next, we need to subtract the tens. We know the number 58 has five 10s. And we need to subtract two 10s. The number 26 has two 10s. We had five 10s. We’ve subtracted two 10s. We have three 10s left. 58 subtract 26 equals 32.

When we’re subtracting a two-digit number from a two-digit number, the first step we can do is to model the number we’re subtracting from. This is the correct model to show the number 58. When we’re subtracting a two-digit number from a two-digit number, we always start by subtracting the ones first. Then we subtract the tens. 58 subtract 26 equals 32. We used our knowledge of place value to help us subtract.