Compare fractions with like and unlike denominator

Two fractions can only be compared fairly when their pieces are the same size. With a shared denominator, the numerators do all the talking: 30/40 beats 13/40 because 30 pieces beat 13 of the same piece.

With unlike denominators, the page models four steps on 5/8 and 7/4: list multiples, find the LCD of 8, scale each fraction, then compare 5/8 with 14/8. Two of the last pairs, h and j, reward a different eye, since 2/6 and 1/3 are the same number written two ways, and so are 6/9 and 2/3.

The page works on 4.NF.A.2, comparing fractions with different numerators and denominators.

The same-denominator rows review 3.NF.A.3.d.

Pair e, 9/7 against 4/5, is where the old habit shows. A child who trusts the bigger denominator, or simply the bigger digits, picks wrong and moves on. "Is 9/7 more or less than one whole?" That single question settles it, since 9/7 is past 1 and 4/5 is not.

Why does it happen? Whole-number habits say bigger digits win, and fractions break that rule both ways.

Pair g, 13/5 against 11/6, invites the same check with whole parts. Have your child say each answer as a sentence, "Thirteen fifths is greater than eleven sixths," before writing the sign.

A note for parents: the step 2 box on page 1 names 2/9 and 7/5; it means 5/8 and 7/4, as page 2 shows.

In Full House: An Invitation to Fractions, Dayle Ann Dodds fills an inn with guests who each take one eighth of a cake, which turns 5/8 against 14/8 into a picture your child can draw.

At home, cut one pizza into 8 slices and another into 4. Is 3 of the quarters more or less than 5 of the eighths? Let your child prove it by stacking slices.

While you bake, fill a measuring cup to 2/3 and another to 3/4 and compare the heights.

Whatever the score, notice the method: "You checked each pair against one whole before guessing." The next page puts these comparisons inside word problems.