Video: Subtracting Tens and Ones on a Blank Number Line

Look at how Noah subtracted 32 from 59 by taking away 3 tens and then 2 ones.

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Video Transcript

Look at how Noah subtracted 32 from 59 by taking away three tens and then two ones. 59 take away 10 is 49. 49 take away 10 is 39. 39 take away ten is 29. 29 take away one is 28. And 28 take away one is 27. 59 subtract 32 equals 27. Use number lines to find the answers to these problems. 71 subtract 23 equals what. 92 subtract 16 equals what.

In the first problem, we have to calculate 71 subtract 23. So we’re going to start at number 71. The two digit in the number 23 is worth two tens or 20. And the three digit is worth three ones. First, we can take away two tens and then three ones. 71 take away 10 is 61. 61 take away 10 is 51. Now, we have to take away three ones. 50, 49, 48. 71 subtract 23 equals 48. We partitioned the number we were subtracting, 23, into two tens and three ones. This helped us to find our answer of 48.

In our second problem, we have to start with 92 subtract 16. And we can partition 16 into one ten and six ones. So we’re going to subtract 10 and then six ones. 92 take away 10 takes us to 82. Now, we need to count back in ones six times. 81, 80, 79, 78, 77, 76. We started at 92 and subtracted one ten, which took us to 82. Then we took away six ones. 82 subtract six ones is 76. So 92 subtract 16 equals 76.