Whole Number ÷ Unit Fraction
Whole Number Divided by Unit Fraction is a Grade 5 math skill from Eureka Math that teaches students to divide a whole number by a unit fraction such as 1/2, 1/3, or 1/4. Students learn that 6 ÷ 1/3 asks how many thirds are in 6, and the answer is 18. This skill uses tape diagrams and the invert-and-multiply rule to connect visual reasoning to the procedural algorithm.
Key Concepts
Dividing a whole number, $a$, by a unit fraction, $\frac{1}{b}$, is a way of asking: "How many groups of size $\frac{1}{b}$ are in $a$?" This can be modeled visually to find the total number of fractional parts.
Common Questions
How do you divide a whole number by a unit fraction?
Ask how many of that fractional unit fit into the whole number. For example, 4 ÷ 1/2 asks how many halves are in 4. Since there are 2 halves per whole, there are 8 halves in 4.
What is the rule for dividing by a unit fraction?
To divide by a unit fraction 1/n, multiply by n (the denominator). For example, 5 ÷ 1/4 = 5 x 4 = 20.
Why does dividing by a fraction less than 1 give a larger result?
Because there are more fractional pieces in a whole than there are wholes. Fitting small pieces into a larger quantity always results in a larger count.
What Eureka Math Grade 5 chapter covers whole number divided by unit fraction?
Eureka Math Grade 5 Chapter 25 covers division of fractions, including dividing whole numbers by unit fractions using models and the standard algorithm.
How does a tape diagram model whole number division by a unit fraction?
Draw a tape for the whole number, then mark off unit-fraction-sized segments. Count the total segments to find the quotient.