Question

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

Answer 1

gotan example to work on?

Answer 2

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

Answer 3

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

Answer 4

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

Answer 5

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
\( 1 \frac{1}{2} \)