Today in Math class, we began renaming with addition problems! We focused on a basic fact, such as 7 + 5 = 12, and identified the 2 in the ones place. Next, we solved 67 + 5 = 72, noticing the basic fact of 7 + 5 in the ones places. One strategy is to break apart 67 into 60 and 7, add 7 and 5, and then add 60 + 12. Another strategy is rewrite the problem in straight columns, which I strongly encouraged. This helps the kids clearly see the place value positions. We also talked about what would happen if you were 67 years old and grew 5 years older. You wouldn’t be in your 60’s anymore, you would be in your 70’s. That’s why the tens place changes. We also modeled problems like this, using a place value chart and circles representing ones and tens. When there were 10 or more ones, it was time to “make an exchange,” trading 10 ones for a ten.
Next, we worked on the more challenging problem of 367 + 5 = 372. We referred back to what we already knew (67 + 5), and simply added 3 hundreds. I am fine with the students using whichever strategy they are the most comfortable with (mental math, adding in straight columns, using a hundred chart, etc). If your child is struggling with this work, please don’t worry. Having hands-on experience this week should make the concept more concrete. You can also review the place value positions (ones, tens, hundreds) to make sure that skill is mastered.