Welcome to my first, simple, math post. This is, as you might have guessed, is a math post for……probably, 5th and 6th graders. But, you have to use your brain a lot! Today’s topic: DECIMALS AND FRACTIONS!
Before knowing this, you must know the LCM or the Least Common Multiple is a common number which is the common multiple between two numbers but it is the lowest common factor. There is a really easy way of finding LCM called the DIVISION method.
eg- 12, 18
As you see, you take the two no.s and divide by a common factor. But, if the 2 no.s don’t have a common factor, divide one no. by a prime* factor but leave the other alone. Then, divide the other other by a prime* factor. Umm….don’t forget to multiply the no.s (factors) to get the real LCM.
(*- Must be a factor)
Now, I want you guys to solve questUHNZZZZ….!
” Find the common factors of 243, 273, and 369″
” Find the common factors of 511, 84, and 647″
When it comes to addition of fractions, we quite get to use the LCM. If we want to add 2 fractions…..
……..we only have to find the LCM of b and d, the denominators only. Then, we have to multiply both the sides of the fraction such that both denominators have the same fraction. Then, simply add the numerators. But, remember……try to put in the simplest form.
Same comes to subtraction. But, in the second last step, you have to subtract the numerators with the same denominator.
In this operation, you just have to simply multiply the numerator and denominator. Simplification of the fraction is important.
If you have two fractions and multiply them, it will be like this-
In this simple operation, if you have two fractions a/b and c/d, then, we have to find the reciprocal/ in short words, switch between the numerator and denominator. Then, we get, a/b × d/c = ad/bc
Now, many students are familiar with decimals, but we’ll go through a simple, short summary-
- Decimals have places increase by going more to the left. The real decimal places end in ‘ths’
- In decimal addition/subtraction, we add more zeroes to a decimal place such that the decimal places are equal to the number with more decimal places.
- In decimal multiplication, we take the two decimal numbers and remove the decimal point from it and normally multiply. In the result, you must count the decimal places to the right in the numbers and add them. Then, start at the result from the right and move the total no. of places you’ve got.
- In decimal division, you must make the problem into a fraction and multiply both sides by a no. such that the decimal point in the denominator vanishes. Then, divide normally.
- When you multiply/divide by 10, 100, 1000, etc., you must move the decimal place of the other no. to the left/right by the number of zeroes in the other number.
0.978 × 9.7512
Put your answers in the comments below! HOPE YOU ENJOY!