Two Digits with Numerals (1)
Next, in 3 meetings, over a period of 1 week,
I helped my student to work from numerals alone - only IMAGINING the icons. Here is her
first attempt.
What To Look For In This Video
I introduced the idea of working with numerals alone for the problem 72 - 33. She used the same strategy that she had used with, and perfected with, the icons. Her logic continued to be excellent, but without the icons in front of her she made one small mistake. Here are the details.
- She started by taking 3 tens from the 7 tens and recorded 40.
- Recognizing that she started with only 2 ones while needing to take away 3 ones, she plans on taking the 3 ones from one of the remaining tens.
- That caused her to realize that the difference will be in the 30s, not the 40s. So she recorded 30.
- She knows that 10 - 3 = 7, so she records 37.
- But she forgot that she had 2 ones to start with, so the correct answer is 39 (37 + 2).