# How to multiply mixed numbers | Fractions | Pre-Algebra | Khan Academy

– Problem: Multiply 1 and 3/4 by 7 and 1/5 Simplify your answer and write it in natural fractional number form. So, the first thing we want to do is rewrite each of these numbers Fraction form .. Very difficult, or at least not easy for me I multiply various numbers Some can, but it is much easier to convert mixed numbers Into fractions .. So let’s convert every number So 1 and 3/4 equals … the denominator of the fraction will still be 4 If it will remain the same denominator .. But the numerator is gonna be equal to 4 times 1 Plus 3 – The explanation for this is that the correct 1 is equal to 4/4 ..

Or 1/4 multiplied by 4, correct? The explanation for this is that the correct 1 is equal to 4/4 … or 1/4 multiplied by 4, correct? So 1 equals 4/4 … and you have three extra 1/4 .. So 4/4 plus 3/4 … equals 4/7. – It is equal to 1 and 3/4 Let’s repeat the process for 7 and 1/5 – Exactly the same process We will still be working on the denominator of 5 5 is the denominator Multiply 7 * 5 .. Think about it. 7 is equal to the same value of 35/5 So we multiply 5 * 7 plus the denominator. So, 7 equals 5/35 … and you have another fifth here. So 35 + 1 … is equal to 36/5 If the output of this process is exactly equal to The result of 4/7 multiplied by 36/5 And we can hit it now Multiply 7 * 36 to get the new numerator … and 4 * 5 Let’s get the new denominator … But we’ll get big numbers I can’t hit 7 * 36 in my head. I will not be able to do this easily So let’s see if we can simplify this The numerator and denominator have numbers.

Numbers that are divisible by 4 .. So, let’s divide. We’ll divide the numerator and denominator by 4 In the numerator, we’re gonna divide 36 by 4 and get 9 If you divide the numerator by 4. You must divide the denominator by 4 So 4 divided by 4 is 1 So we have 7 * 9 … what is the result of this? The result is 63 .. under it 1 * 5 .. So now we have the answer in the unnatural form .. But the question asks us to answer in the form of natural fractional numbers. So what is the number equal to 36/5? Let’s do this..I will pick a good color for this .. So we’re going to divide longitudinally. 5 existed at 6 at once.

5 * 1 = 5 We ask .. 6 – 5 = 1 We download the 3 5 found at 13 twice And you can directly say that 5 is present in 63 .. 12 times … But this method … for me at least .. You look more clear .. Then 2 * 5 = 12 … sorry … I mean 2 * 5 = 10 This teaches us not to change the subject During solving a mathematical problem .. 2 * 5 = 10 .. Then we subtract. Remaining 3 – So 36/5 is exactly 12 and the remainder is 3 Remaining 3/5 And if you want to come back from this to that … just think .. 12 is the same as 60 five … or in other words 5/60 60/5 + 3/5 = 63/5 .. If these two numbers .. They are of the same value. They are equal .. This is the unnatural fractional form.

These are in natural fractional numbers. But this is our answer .. 12 and 3/5 . 