To subtract one fraction from another, like 2/3 – 1/4, model the minuend 2/3 using a 2-unit rod over a 3-unit rod and the subtrahend 1/4 using a 1-unit rod over a 4-unit rod. To find a common denominator, create a train of 3-unit rods and a train of 4-unit rods until both are the same length. Both trains have the same length when they are 12 units long, so 12 is a common denominator. The fractions 2/3 and 1/4 can be expressed as equivalent fractions 8/12 and 3/12. Because the denominator represents the number of equal parts in a whole and the numerator represents the parts in the quantity, subtract the numerator 3 from the numerator 8. There are 5 parts remaining, so 2/3 - 1/4 equals 5/12.
Subtracting Fractions using the Brainingcamp Cuisenaire® Rods virtual manipulative.
Brainingcamp virtual manipulatives can be used anywhere with no setup, cleanup, or lost parts. They are highly effective at engaging today’s digital learners and helping them bringing abstract math concepts to life.
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