🥣 Fraction Kitchen

Measuring cups only pour together when their marks line up. Find the common mark, then add or subtract.

REMEMBER: You can only add or subtract pieces of the same size. Thirds and fourths are different sizes, so first trade each fraction for an equivalent one with a common denominator — a mark both cups share. Then add or subtract the numerators only; the denominator names the piece size and stays. Never add across (2/5 + 1/2 is not 3/7 — 3/7 is less than 1/2, and you added something to 1/2!). Always estimate with benchmarks (0, ½, 1) before trusting an answer.

Part 1 · The Pour Station

Two measuring cups hold two fractions of a cup. To pour them together (or pour one out of the other), every mark on both cups must line up. Pick a number of marks per cup. If both fractions land exactly on marks, the pour works. If not, try another.

Denominators 2 to 12. Keep each cup under 2 cups; for pouring out, the first cup must hold at least as much as the second.

Marks per cup

Part 2 · The Taste-Test Estimator

Every order passes the taste test before it goes out. First decide roughly how much the order makes — using 0, ½, and 1 cup as benchmarks — and lock it in. Then pick the exact amount. The taste test catches impossible answers.

TASTE TEST

Part 3 · The Machines

Three step-by-step machines. Each step says what to do and why.

Add or subtract two fractions

    Add or subtract mixed numbers (with regrouping)

      Is this answer reasonable? (Check before you trust it)

        Part 4 · Head Chef Quiz

        Ten questions. Each wrong answer tells you which station to revisit.

        Question 1 of 10 Score: 0

        Word Box

        Numerator · Denominator
        In 3/4, the denominator 4 names the size of the pieces (fourths); the numerator 3 counts how many.
        Unlike denominators
        Different piece sizes, like thirds and fourths. They cannot be added until they are traded for a common size.
        Equivalent fractions
        Different names for the same amount: 2/3 = 8/12. Multiply numerator and denominator by the same number.
        Common denominator
        A piece size both fractions can be written in — a mark both cups share. Any common multiple of the denominators works.
        Least common denominator (LCD)
        The smallest common denominator — the least common multiple of the denominators. Smaller numbers, less simplifying later.
        Mixed number · Improper fraction
        1 5/12 is a mixed number (whole plus fraction); 17/12 is the same amount as an improper fraction (numerator larger than denominator).
        Regroup
        Trade one whole for pieces (1 = 4/4) so you can subtract, or trade pieces for a whole when a sum goes past 1.
        Benchmark
        A friendly amount to compare against: 0, ½, 1. Knowing 2/5 is a little under ½ lets you estimate before computing.
        Simplest form
        A fraction whose numerator and denominator share no common factor except 1: 10/12 simplifies to 5/6.
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