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Why must you multiply by the reciprocal when dividing fractions?
Wiki User
∙ 14y ago
I dont kno. good question
From Kevin: I have the problem in Math class today in school. And this is what I came out with:For just a moment, don't think 2 numbers as fractions, think of them as x and y. X divided by Y
When X divided by Y (or "Y over 1"), you can write it as : X times "1 over Y". Thus you get a statement: "When a number was divided by another number, the answer shall equal to the first number times the reciprocal of the second number."
Same statement goes with fraction. Understand?
Wiki User
∙ 14y ago
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How do you solve this equation x over 9 equals 12?
x/9=12 multiply both sides by 9, giving x=108 ____________________________________________________________________ To solve the problem 'x over nine equals twelve', you must first recognize that any number over another number (which includes variables) is a division problem. Thus, all fractions are division problems. You have to multiply by the reciprocal, and multiplication is the opposite of division, and the reciprocal in this case would be 9/1, or just 9. You must apply this to both sides of the equation, so x/9 times 9 is x, and 12 times 9 is 108. Therefore, x =108.
How do you find the reciprocal of a whole number?
To find the reciprocal of a whole number, you must first write it as a fraction. You do this by writing x/1, if the number is 4, it would be 4/1. Then you would find the reciprocal of that fraction. So using the same example, the reciprocal of 4 is 1/4.
What is a unlike fraction?
You must have 2 fractions or more to have unlike fractions. They are fractions with different denominators such as 7/8 and 1/2. Like fractions would have the same denominator like 7/8 and 4/8.
Multiplying fractions and mixed numbers?
can't do it as is... you must convert the mixed number to an improper fraction to multiply To convert the mixed number to a fraction you multiply the denominator and the number in front and then add that to the numerator then you put that number over the original denominator ex. 2 1/3 = (3 x 2 + 1)/3 =7/3 then you can multiply: 7/3 X 4/5 = 28/15
How do you solve an inequality in one variable?
It depends on the specific inequality. In the simplest cases, it is solved just like an equation; except that you must be careful when multiplying and dividing - if you multiply or divide both sides by a negative number, you must switch the inequality sign. For instance, a "less-than" sign would be changed to a "greater-than" sign.
What do you do when you are dividing a fraction?
When dividing a fraction you leave the first fraction as it is and you change the second fraction into a reciprocal (flip the fraction). Once you have changed the second fraction into a reciprocal, then you would simply *multiply the two fractions together. Once you multiply the two fractions then that would be your final answer. Dont forget to simplify! And remember if the fractions are mixed numbers before you do anything you must change the mixed numbers into improper fractions first! hope this helps! *If you dont know how to multiply fractions then thats a different question
Why do you use the reciprocal when dividing fractions?
Think of it like this.... If we are dividing fractions and we set those fractions up in a fraction such as, 2/3 ___ 3/4 then how would we get rid of the bottom fraction? We would multiply it by the reciprocal 4/3, so that it's now equal to one, and then because we multiplied the bottom by 4/3, we must also multiply the top by 4/3. So now we have... 2/3 * 4/3 _______ 3/4 * 4/3 = 8/9 ___ 1 = 8/9 That's why we multiply by the reciprocal of a fraction when dividing! E2020 people this should be in your notes? The reciprocal is one of two numbers whose product is 1; it is also called multiplicative inverse.
Why is it useful to know what a reciprocal is in math?
A reciprocal is useful to know in math because to divide fractions, you must multiply by the second fraction's reciprocal. For example: 2/3 divided by 4/7 is the same as 2/3 times 7/4.
When multiplying fractions you must multiply the numerators together and multiply the denominators together?
true
How do you find a reciprocal?
A reciprocal is the number you must multiply another number by to get the product of 1. The reciprocal of 4 (which is the same as 4/1) is 1/4. The reciprocal of 3/8 is 8/3. The reciprocal of 13 is 1/13.This can also be expressed using exponents. The reciprocal of any value x is equal to x-1. So the reciprocal of a/b is (a/b)-1, which is equal to b/a.To find a reciprocal, put the number under one. If it is a fraction, flip the fraction. Whatever the reciprocal is, remember that it must always multiply to one with the original number.
What fractions have the same value?
5/10 is equal to 1/2. Whatever you multiply the numerator by you must multiply the denominator and you will always get same valued fractions
When do you add fractions when baking?
In order to add fractions, they must have the same denominators. If the fractions you wish to add do not already have the same denominators, they can be made to do so by finding the right number by which to multiply both the numerator and the denominator of each fraction. To find this number, multiply all the distinct denominators together, then multiply both the numerator and denominator of each fraction by a number found by the dividing the product of the distinct denominators by the denominator of the particular fraction concerned. All the fractions will then have the same denominator. Add the numerators of such fractions together to find the numerator of the sum; its denominator will be the one common to all the fractions.
When dividing two fraction you must filp the fraction over and then multiply?
Yes.
When do you use multiplying and dividing fractions in the real world?
You may not literally say "multiplied by a half" but multiplying and dividing by fractions are equivalents to doing the other function with an inverse number, most easily in that dividing by 2 is the same as multiplying by (1/2). We don't often multiply and divide by fractions because most of the time we can convert such a problem into a nicer one. We may use fractions like this, for example, in a test out of 90 marks where one must score 2/3 to pass. This pass mark is obtained by multiplying 90 by (2/3), though this, as said earlier, would usually, even unconsciously with such convenient numbers, be split into "divide by 3, then multiply by 2".
What happens when you divide a number by 0.5?
When you divide a number by 1/2, you multiply it by 2. Imagine that you are dividing two fractions ; 1/1 / 1/2. In order to divide the fractions, you must flip the second fraction making it 2/1 and then multiply 1/1 by 2/1. This will give you two. Thus 1/0.5=1*2.
How do you you do the mathematical operations in fraction?
To add or subtract fractions, or even just to compare them (verify which fraction is greater), you must first (1) find a common denominator, and (2) convert both fractions to equivalent fractions with the common denominator. Then you just add, subtract, or compare the numerators. For example, 2/3 + 1/6 = 4/6 + 1/6 = 5/6. To multiply fractions, multiply the numerators and denominators separately. For example, 1/3 times 2/5 = (1x2)/(3x5) = 2/15. To divide fractions, multiply the first fraction by the reciprocal (multiplicative inverse) of the second fraction. If the fraction consists only of the numerator, you get the reciprocal by exchanging numerator and denominator. For example, 1/3 divided by 2/5 = 1/3 times 5/2.
Compare and Contrast dividing two fractions and multiplying two fractions?
To add two fractions, you must first convert them to a common denominator, which is the Least Common Multiple of the denominators of the two fractions you're adding. For example, to add 5/6 and 1/8, you convert them to the common denominator LCM(6,8)=24. Then 5/6=20/24 and 1/8=3/24 so the sum is 23/24. To multiply two fractions, you multiply the numerators together and multiply the denominators together. Thus, 5/6 * 1/8 = (5*1)/(6*8) = 5/48. If both fractions are between 0 and 1, then the sum will always be greater than the product.
