Answer:
23/56 centimeters
Step-by-step explanation:
all of the variables have a common denominator, so you can effectively ignore the denominator when solving.
1. you start off with 34/56 centimeter of chalk and Brian breaks off 23/56 centimeters worth, leaving you with 11/56 centimeters
[tex]\frac{34}{56} -\frac{23}{56} =\frac{11}{56}[/tex]
2. Sara then added 12/56 centimeters worth, making the final amount 23/56 centimeters of chalk
[tex]\frac{11}{56}+\frac{12}{56} =\frac{23}{56}[/tex]
An equation to summarize all of this is:
[tex]\frac{34}{56} -\frac{23}{56} +\frac{12}{56}[/tex]
