## anonymous 4 years ago I feel like such a dummy! I cannot figure out how to subtract mixed numbers w borrowing. I am stuck. Any help?

1. amistre64

gotan example to work on?

2. amistre64

and borrowing is fine, the math doesnt mind you borrowing as long as you put it back

3. amistre64

$-A\frac bc=-A-\frac{b}{c}$might be useful to know

4. phi

Maybe this example will help? http://www.khanacademy.org/video/subtracting-mixed-numbers-word-problem?playlist=Developmental+Math

5. phi

Here's an example $$4 \frac{1}{2} - 2 \frac{3}{4}$$ or, making both fractions have a common denominator $$4 \frac{2}{4} - 2 \frac{3}{4}$$ we can think of this as $$4+ \frac{2}{4} - (2+ \frac{3}{4})$$ distribute the negative sign, so this is also equal to $$4+ \frac{2}{4} - 2- \frac{3}{4}$$ now if 2/4 were bigger than 3/4 we could just do (4-2) + (2/4-3/4) Actually, we could do that, but that is an ugly answer. Use this idea: 4= 3+1, and 1= 4/4, so 4= 3+ 4/4 and the problem is $$3+ \frac{4}{4}+\frac{2}{4} - 2- \frac{3}{4}$$ switch terms around to get $$3-2 + \frac{4}{4}+\frac{2}{4} - \frac{3}{4}$$ $$(3-2) + (\frac{6}{4} - \frac{3}{4} )$$ $$1 \frac{2}{4}$$ or, simplifying the 2/4 $$1 \frac{1}{2}$$