The HPs’ Weekly Math Thing #1

We HPs have been gung-ho about promoting literacy and numeracy. We don't really spend hours on our daily Math homeschool lessons (we use Singapore Math, and we usually just do 2 pages of textbook and workbook lessons a day), but we do try to incorporate it into our daily lives.

A few people have been asking how to do that, how to make it a normal part of your day. We aren't experts, and I am definitely not a Math genius, but we're happy to share what has worked for us. Starting this week, I will try my best to post at least one Math-at-Home-Math-in-Real-Life thing that has worked for us. And here is tip#1:

Money has always been a great way to hone Math skills--when we go shopping or even when we pay for toll, I usually ask the kids how much change we should get.

The other day we went to the grocery and Breeze ran ahead to get a couple of boxes of milk. She came back with Southdale, which costs Php68.95 a box. "I got this one coz it's so much cheaper," she said. I asked her by how much--and that flummoxed her for a bit. To help her along, I gave her a quick Math shortcut called "Subtraction by Steps" (which I learned from MATH-Inic). Basically, we rounded up 68.95 to the nearest base (or multiple of 10), which is 70 and proceeded from there. It's so much easier to subtract 70 from 84.50, right?

So we round up to 70, and subtract from 84.50, and end up with 14.50. Breeze figured out pretty quickly that she had to add back the extra that she subtracted when we rounded up. For that, she used another shortcut we learned previously, called "Completing the Whole." This one is easy--it's knowing what numbers you need to complete the whole, or make the number end in zero (or make it a multiple of 10). She did this in steps too--first she needed 0.05 to make 0.95 into 1; then she needed 1 to make 8 + 1  into the next multiple of 10 (the 8 is from the 68, and the 1 is from the 0.95 + 0.05, in case I lost you). So she needed to add back 1.05.

So how much do we save by getting Southdale instead of Nestle? 14.50 + 1.05 or Php15.55--pretty much what she would need to buy a pack of her favorite popsies. Breeze figured that out in less than a minute.

Not only was that a lesson in mental Math, but also a lesson in budgeting, priorities, and decision making. So win-win all around.

Do you have any real-life Math tips you'd like to share? Or any burning Math questions that you have? Leave a comment!


Math practice in real life--how much do you save by getting the cheaper brand of milk?


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