Tuesday, April 12, 2011

Math Class

I love learning with Stockton. Sometimes I'm amazed of the things I don't know. I probably learned them way back when, but still . . . how could I forget? Today we were learning 'tests for divisibility'. There are ones that are obvious, like an even number is always divisible by 2, a number ending in 5 or 0 is always divisible by 5, and a number ending in a 0 is always divisible by 10. I vaguely remember learning some of the others . . . . Feel free to skip the math lesson coming up, but I find this fascinating.

4 - If a (whole . . . all of these are for whole numbers . . . probably) number is divisible by 4, just check the last two numbers . . . 7,736 is divisible by 4 because 36 is divisible by 4. 86,222 is not because 22 is not divisible by 4.

3 & 9 - If the sum of the digits is a multiple of 3, then it is divisible by 3. If the sum is a multiple of 9, it is divisible by 9. 393 is a multiple of 3 but not 9 because 3+9+3=15.

6 - If a number is divisible by 2 & 3, then it is divisible by 6. 31,027,302 is divisible by 6 because it is even, so 2 is a factor, and 3+1+0+2+7+3+0+2=18 making 3 a factor. Both 2 & 3 are a factor so 6 is.

11 - 11 was the craziest one and I'm sure I never learned this. I will quote: "A number has 11 as a factor if and only if the sum of its first, third, fifth, . . . digits equals the sum of its second, fourth, sixth, . . . digits, or if these two sums differ by a multiple of 11." Wow. So, 17,314 has a factor 11 because 1+3+4=8 & 7+1=8. Also, 806,124 has 11 as a factor because 8+6+2=16 & 0+1+4=5. 16-5=11. Crazy.

Enough about that, now what else happened today? After we got the kids to bed, Mike and I went to Bubs & Ange's house to drop off extra boxes. Lincoln is obsessed with Minute to Win It. He was showing me different games that I think he made up, but I'm not sure. Ella & Abbs are so stinking cute. Abbs doesn't stop smiling and Lincoln & Ella had a great time playing in a giant box that Mike put over Lincoln's head.

After we dropped off the boxes and stopped by Hires for a root beer, we headed up to Mike's house. Several trees had fallen over during one of the storms. Mike's dad and his brother had chopped them up for firewood for us. We went and picked them up. It filled the entire 'kidnapping van' that Mike had. (Mike has been driving a van he calls the kidnapping van because it is a carpet cleaning van that has no windows in the back, and doors out the side . . . well, it's hard to explain but it is funny.) Anyway, we have a ton of firewood that we are very grateful for. I would have taken a picture, but I was way too tired. Maybe tomorrow.

While we were up there we checked on Talon. Actually Mike went up there with Jorja earlier today to check on the cat. He told me that Talon was limping. When I saw him I was so sad. It was pathetic to see this cat hopping around. Mike and I gathered up Talon's things (food, litter box etc.) and took Talon home with us. I hope I don't regret this, but I kind of know how Talon feels. Discarded. I have felt that before and it is horrible. So, we brought Talon here with us at least until his leg heals. We will then try to figure out what we should do. I'm predicting a very happy Porge in the morning.

2 comments:

brett said...

Steph, I would also like to point out that 31,027,302 (your example for #6) is divisible by 9. I don't think I knew any of those tricks except for the 3 trick (and the 2 and 5 ones). I think there is a trick for 1, but I can't remember what it is.

On an unrelated note, turns out I will be there until my flight leaves on Wednesday. Yah!

Stephanie said...

Can't wait to see you!