How do you multiply $1 1/4 div 7$ ?

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Answer 1 · 2016-06-08T00:18:26

$5/28$

Firs, rewrite $1 1/4$ as an improper fraction. Do this by recognizing that

$1 1/4=1+1/4$

Now, to add these fractions, we need a common denominator. Note that:

$1+1/4=1/1+1/4$

The common denominator will be $4$ , since it is the least common multiple of $1$ and $4$ .

$1/1+1/4=(1xx4)/(1xx4)+1/4=4/4+1/4$

We can do $4/4+1/4$ since the fractions have the same denominator: add the numerators, $1$ and $4$ , and leave the denominators the same. Thus

$4/4+1/4=(4+1)/4=5/4$

So, instead of the original equation $1 1/4-:7$ , we have the new equation

$5/4-:7$

The next step is to note that dividing by $7$ is the same as multiplying by the reciprocal of $7$ .

You may be confused, since $7$ doesn't seem to be a fraction, so how can it have a reciprocal?

However, note that $7=7/1$ . Thus, the reciprocal of $7$ is the same as saying the reciprocal of $7/1$ , which is $1/7$ .

So, saying $5/4-:7$ is equal to $5/4xx1/7$ .

To multiply fractions, multiply the numerators straight across and the denominators straight across.

$5/4xx1/7=(5xx1)/(4xx7)=5/28$

$5/28$ cannot be simplified since $5$ and $28$ share no common factors other than $1$ .

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