How do you evaluate $4 \times 2 \frac{1}{2} + 5 \frac{3}{4}$ $4\times 2\frac{1}{2}+5\frac{3}{4}$ ?

Question

1233 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-09-24T03:37:04

63/4 or 15.75

You can choose to do this in fractional or decimal form. I'll go through both.

Decimal
$2 \frac{1}{2} = 2.5 and 5 \frac{3}{4} = 5.75$ $2 1/2 = 2.5 and 5 3/4 = 5.75$

So equation becomes $4 \times 2.5 + 5.75 = 10 + 5.75 = 15.75$ $4 times 2.5 + 5.75 = 10 +5.75=15.75$

Fractions
First rearrange everything so it's all improper fractions.

$\frac{4}{1} \times \frac{5}{2} + \frac{23}{4}$ $4/1 times 5/2 + 23/4$

Rule for multiplying fractions: top times top, bottom times bottom.

$\frac{4}{1} \times \frac{5}{2} = \frac{20}{2} = 10$ $4/1 times 5/2 = 20/2 = 10$

Now we have $\frac{10}{1} + \frac{23}{4}$ $10/1 + 23/4$

Rule for adding fractions: **add the top line IF the denominators (bottom line) are equal. **

It's easier to make $\frac{10}{1}$ $10/1$ have a denominator of 4, because 23 is a prime number so we can't divide it by anything except itself.

$\frac{10}{1} + \frac{23}{4} = \frac{40}{4} + \frac{23}{4}$ $10/1 + 23/4 = 40/4+23/4$

Now add the top lines:

$\frac{40}{4} + \frac{23}{4} = \frac{63}{4}$ $40/4 +23/4 = 63/4$

How do you evaluate 4×212+5344\times 2\frac{1}{2}+5\frac{3}{4}?