Subtracting a Fraction from a Whole by Converting the Whole
Subtracting a Fraction from a Whole by Converting the Whole is a Grade 5 math skill from Eureka Math. Students rewrite a whole number as a mixed number before subtracting a fraction. For example, 6 - 3/4 becomes 5 4/4 - 3/4 = 5 1/4.
Key Concepts
To subtract a fraction from a whole number, convert the whole number $W$ into an equivalent fraction with the same denominator $d$ as the fraction being subtracted: $$W \frac{a}{d} = \frac{W \times d}{d} \frac{a}{d} = \frac{(W \times d) a}{d}$$.
Common Questions
How do you convert a whole number to subtract a fraction?
Borrow 1 from the whole number and convert it to a fraction with the same denominator. For example, 5 - 2/3 = 4 3/3 - 2/3 = 4 1/3.
What Eureka Math Grade 5 chapter covers this skill?
Eureka Math Grade 5 covers subtracting a fraction from a whole by converting the whole in its fraction subtraction chapters.
Why must you convert the whole before subtracting a fraction?
You cannot subtract 3/4 from 0. Converting gives the whole a fractional part large enough to subtract from.