Bunny has one of those preschool skills workbooks here at home. (Great gift, Auntie Susie!)
One of the activities is a picture hunt. It asks to count the number of various items, like trees, apples, and bees.
For the bees, there were two groups of bees. Two bees were in some flowers. Eight bees were swarming next to a hive. She counted them individually to come up with the answer, ten.
Then I asked, “How many bees are in the flowers?”
“Two,” replied Bunny.
“How many bees total?”
She said, “Ten.”
“So how many bees are by the hive?” I asked.
She didn’t know.
So I wrote down and explained the following formula:
B + 2 = 10, and B is for the bees that are by the hive.
Then I explained that to find out the number of bees by the hive, we would take the total number of bees and subtract the bees in the flowers, or:
10 - 2 = B
Then I put up my ten fingers and asked her to count down with me, taking away a finger each time. Nine, eight.
“How many fingers did I put down?” I asked.
She said, “Two.”
“So ten minus two equals?”
“So B equals?”
And I asked her to write B = 8
She was pretty excited about coming to the answer.
Similarly, we did an exercise with JD yesterday that was similar. Every day, they get four Girl Scout cookies after school. We often do math with them by subtracting the number of cookies they’ve eaten from the total number of cookies to come to the number of cookies they have left.
Yesterday, however, I changed that a little bit. JD had eaten two cookies. I asked him to say it in a number sentence:
“Four minus two equals two.”
Then I asked him, “How many cookies did you just have?”
“How many cookies did you eat just now?”
“So say that in a number sentence.”
“Three minus one equals two.”
We have a white board on the wall next to the kitchen table. I wrote the number sentences and had the kids recite them as I did so:
4 - 2 = 2
3 - 1 = 2
Then I said, “So if four minus two equals two and three minus one equals two, then . . .” and I wrote:
4 - 2 = 3 - 1