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Lesson 61: Dividing Larger Numbers
If you are in high school or college, it is likely that you are allowed to use a calculator on every exam. Still, it is important to have a general idea of how basic arithmetic works. In this lesson we'll look at dividing larger numbers.
Before starting this lesson, review Lesson 45. Take a look at the first problem below. First we'll check to see if 12 divides into 3. Of course it doesn't, so we'll move on and see if it divides into 38. If we count by 12s, we can see that it goes in 3 times, with a remainder of 2. We can write the 3 above the line, in the column above the 8, and write a little 2 to the left of the 6. The 6 now really becomes 26, and we can see how many times 12 goes into it. It goes in twice, with a remainder of 2. We can write a 2 above the line, and then we are just left with a remainder of 2 which we can notate as shown.
Look at the next problem. Here we will check to see if 15 goes into 7, and it does not, so we'll check to see if it goes into 75. It does, exactly 5 times, so we'll write a 5 above the line as shown. Now we'll see if 15 divides into 4. It does not, so we must write a 0 above the line. We didn't have to bother writing a 0 at the start, because that would just start our quotient with a 0, which wouldn't matter. What we do now is look at the 4 and the 3 as 43, and see how many times 15 divides into it. It goes in twice, and there is 13 left over. We write a 2 as shown, followed by the remainder.
As you move onto more advanced math, you'll see that instead of writing remainders, we'll determine the decimal component of the quotient, and we'll include that in our answer. For example, a quotient might be something like 7.25, or 91.333. Sometimes we have to use special notation to show that a decimal goes on forever. You'll learn about that later.
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