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MathIsland
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Numbers · from bundles to smaller units

Read the same amount in new ways.

Bundle ones into tens or split a whole into smaller parts. Notice what stays the same. Explore the reasons in pictures and words before memorizing procedures.

Begin with hundreds →Begin with the first fraction story →Revisit tens if they are unfamiliar →

Calculate by regrouping

  1. 1 / 15

    Ten tens make a hundred

    Read three-digit numbers with ones, tens and hundreds, including a zero placeholder.

  2. 2 / 15

    Regrouping in addition

    Add like places and explain why ten of a unit become one of the next unit.

  3. 3 / 15

    Unbundling in subtraction

    Unbundle tens and hundreds to subtract, including across zero, while preserving the starting amount.

  4. 4 / 15

    Multiply tens and ones

    Split a two-digit number into tens and ones, multiply both parts and recombine.

  5. 5 / 15

    Divide by unbundling what remains

    Share tens, unpack leftover tens into ones, and account for the remainder in the original total.

Read and calculate with fractions

  1. 6 / 15

    Write equal parts of one whole

    Choose one whole, then read a fraction as equal parts and the number of those parts taken.

  2. 7 / 15

    Fractions on a number line

    Partition the interval from 0 to 1 equally and locate a fraction as a distance from zero.

  3. 8 / 15

    Fractions beyond one whole

    Express an improper fraction as whole units and remaining parts, and connect it to a mixed number.

  4. 9 / 15

    Equivalent fractions: new parts, same amount

    Explain equivalent fractions by subdividing every part equally while preserving the amount.

  5. 10 / 15

    Compare fractions using equal-size parts

    Compare fractions of the same whole by common units or by part size when numerators match.

  6. 11 / 15

    Add and subtract matching fraction units

    Add or subtract numerators when units match; first find common units when denominators differ.

  7. 12 / 15

    A part of a part: multiplying fractions

    Use an overlap diagram to find a fraction of a fraction of the original whole.

  8. 13 / 15

    How many groups of that size fit?

    Compare an amount and group size in common units, including fractional numbers of groups.

Connect fractions to decimals

  1. 14 / 15

    Place value to the right of the decimal point

    Read decimal places as tenths and hundredths and explain why 0.3 equals 0.30.

  2. 15 / 15

    Compare, add and subtract decimals by matching units

    Read decimals in common fraction units to compare, add and subtract with aligned place values.

Pause after one story or skip familiar ideas. Read together and point to pictures when text feels difficult. Your next story is never locked behind a quiz score.