Find the missing numerator or denominator in addition and subtraction sentences

Learning Objectives Identify the unknown part (numerator or denominator) in a fraction addition or subtraction sentence. Apply inverse operations to isolate the unknown fraction in an equation. Find a common denominator when adding or subtracting fractions with different denominators. Solve for a missing numerator in an addition or subtraction sentence involving fractions. Solve for a missing denominator in an addition or subtraction sentence involving fractions. Verify their solution by substituting the found value back into the original sentence. Have you ever tried to bake a cake but realized you're missing an ingredient? 🍰 Sometimes in math, we have a 'recipe' (an equation) but a 'missing ingredient' (a number or part of a fraction)! In this le...

TermDefinitionExample NumeratorThe top number in a fraction, representing the number of parts being considered out of the whole.In the fraction 3/4, '3' is the numerator, meaning 3 parts are being considered. DenominatorThe bottom number in a fraction, representing the total number of equal parts that make up the whole.In the fraction 3/4, '4' is the denominator, meaning the whole is divided into 4 equal parts. Equivalent FractionsFractions that represent the same value, even though they have different numerators and denominators.1/2 and 2/4 are equivalent fractions because they both represent half of a whole. Inverse OperationsOperations that undo each other. Addition is the inverse of subtraction, and subtraction is the inverse of addition.If you add 5, you can undo...

Rule for Finding a Missing Addend If $a/b + X = c/d$, then $X = c/d - a/b$. To find a missing fraction (X) that is being added to another fraction, subtract the known fraction ($a/b$) from the sum ($c/d$). Remember to find a common denominator first if needed. Rule for Finding a Missing Minuend If $X - a/b = c/d$, then $X = c/d + a/b$. To find a missing fraction (X) from which another fraction is being subtracted, add the known subtracted fraction ($a/b$) to the difference ($c/d$). Remember to find a common denominator first if needed. Rule for Finding a Missing Subtrahend If $a/b - X = c/d$, then $X = a/b - c/d$. To find a missing fraction (X) that is being subtracted from another fraction, subtract the difference ($c/d$) from the starting fraction ($a/b$). Remember...