Common Core Mathematics 35    Cluster  Use equivalent fractions as a strategy to add and subtract fractions.    Topic  Number and OperationsFractions 
    Grade 5     5.NF.2.  Solve word problems involving addition and subtraction of fractions
referring to the same whole, including cases of unlike denominators,
e.g., by using visual fraction models or equations to represent the
problem. Use benchmark fractions and number sense of fractions
to estimate mentally and assess the reasonableness of answers. For
example, recognize an incorrect result 2/5 + 1/2 = 3/7, by observing that
3/7 < 1/2.    

