Jan 31, 2012

Subtracting Apples from Bob

HT here.
This week, we will focus on subtraction. Which is as easy as taking apples from Bob.
Subtraction is the exact opposite of addition, so the methods you've learned for doing addition can be used for subtraction, with slight tweaking.

Take 6-4 for an example. We will use the l's method, thus;

As you can see, it's very similar to the l's addition method that you learned.
All you need is a good grasp of addition, and subtraction will be as easy as stealing cookie jars from the cookie. Oh, I mean, cookies from the cookie jar.
Once you have single-digit subtraction down-pat, 2-digit, and even larger subtraction problems will be a piece of cake. Work from right-to-left, subtracting the 1's first, then the 10's, and so on.
Take 17-11 for example. Subtract 7-1 to get 6, and subtract 10-10 to get 0. So your answer will be 06, or since the zero is only a placeholder, and not needed at the beginning of a number; 6.
Sometimes, you will get a scenario like this;
32-27=... dividing it into 1's and 10's, you get 2-7 and 30-20. Starting with 2-7, we run into a problem. 7 is greater than 2! What do we do? Simple, cross off the 3 in 32, and replace it with a 2, like this 20-20. now add that 10 to the 2, like this 12-7. Now it's easy to find the answer. 12-7=5, and 20-20 = 0, so your answer is 5
If the number you are subtracting with is greater than the number you are subtracting from, the easiest way to figure out the answer is to reverse the subtraction and then add a "-" sign to the answer.
Thus. 45-47=, 47 is greater than 45, so, switch it around, and subtract 47-45 to get 2. now, simply add a "-"sign to the answer, -2

Alright, here're some test questions to get you started. And remember, as before, keep your eyes open for subtraction problems.


Jan 23, 2012

Addition L2

Alright, HT here again.
Now we're going to be looking at larger addition problems. 3, 4.... even 5-digit additions.

The principle is exactly the same as 2-digit addition, except you have a few extra numbers to keep track of.
So, enough talk, let's get to an example;
115+435... simple enough... let's break it down into 3 single-digit problems. 100+100, 10+30 and 5+5..
We know that 5+5= 10, so let's add another one to the 30, making it 10+40, which equals 50.. now you've got just one problem left.. 100+100.. easy, right? The answer, then, is 250.

4-digit addition? no sweat.
4613+9846... break it down into single-digit additions; 4000+9000, 600+800, 10+40, 3+6.
which gives the answers, 13000, 1400, 50 and 9. Add them together to get 14,459.

And in case you didn't know, it's easier to add from right to left. Yep, you heard me, right to left. Add the 1's first. Then, if you get an answer of 10 or more, add 10 to the 10's place, and remove it from your initial answer. Need an example?

45+36... 5+6 equals 11.. so add 10 to the 10's place.. which gives 50+30, or 40+40... leave the 1 as the initial answer.. then add the 50+30.. which is 80. Add the two answers, 80+1 to get 81.

Your turn!
Try these problems;

Remember, break them down into single-digit additions, and then add the answers.

HT Fact:
The Handsome Toddler encourages you to look for math problems to do.

Jan 16, 2012

Starting out

I'm the Handsome Toddler, and I am here to help YOU learn math with ease.
Ok, enough talk about myself. Let's get started, shall we?
This week, we will just focus on simple, single-digit addition (and a few double-digits). Most of you probably have this down-pat, but a little practice won't hurt, and it will help you get into the habit of actually doing the problems. I know too many instances where someone grabs a math book and reads through it, but does not do the problems because "they're too complicated".

So, first let me show you a few addition problems. Then I will give you a few problems to solve. And the rest of this week, I want you to keep your eyes open for single or double-digit additions. Or you can even make some up.

Ok, first example;
1+1... you're laughing, right? This is so easy. The answer's 2.
Alright, smarty pants, WHY does 1+1= 2? Alright, so you know the answer to that. Good!

Maybe I should say something before I go on to the next example.
2 is equivalent to two 1s.
3 is equivalent to three 1s. and so on.

Alright, on to the next example;
3+6... so, you have three 1s added to six 1s... (1+1+1) + (1+1+1+1+1+1).. now you can count them up. The answer is 9.

A little bit tougher;
6+9... alright, we have six 1s added to nine 1s.. pretty easy, right? let's see (1+1+1+1+1+1) + (1+1+1+1+1+1+1+1+1)... count them up and you get 15.

Ok, we've covered single-digit addition. Now for a few double-digits. If you get stuck, try counting 1s.

27+58... uh oh! where do I start? Well, let's break it down into two problems. You have 20+50 and you have 7+8. Hey, guess what? They're single-digit additions! And since we just covered those, you should get this one pretty quickly. 20+50=70... 7+8= 15... add them together and you get 85.

Last example;
87+92... sometimes double-digit additions have triple-digit answers. But don't panic! First, let's break it down into single-digit additions. 80+90 and 7+2.. You know that 8+9 = 17, so 80+90 must equal 170.. add 9 and you're done. Now, was that so hard?

Congratulations! You're on your way to mastering math. Remember, though you may know some of these steps, you must get to know them so well that you can do them in your sleep.

Alright! Now I've got a few problems for you to solve. And remember, keep an eye open for any other single or double-digit addition problems this week.


HT Fact:
The Handsome Toddler is grateful to Caroline Keeth and Kayla Jade for their inspiration and encouragement. He is also grateful to Mara Clipner for naming him the Handsome Toddler.

See you next week!