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Slices

For ages 8 to 12, and anyone who never quite got fractions

Fractions, one slice at a time.

Short lessons on the ideas that make fractions confusing. Make a guess, move the pieces around, and see for yourself why it works.

Find my first slice See all 20 slices

Try this one

Which is bigger: (one sixth) or (one eighth)?

Two pizzas, exactly the same size. One is cut into 6 equal slices, the other into 8.

(one sixth)
(one eighth)

What happens in a slice

About three minutes each, and nothing is timed.

  1. You guess first

    Pick an answer before anyone explains anything. “I’m not sure” counts.

  2. The picture answers back

    See what your guess means. No red crosses, just a closer look.

  3. You move the pieces

    Cut, fill, slide and stack them until the idea makes sense.

  4. You try something new

    New numbers and a different picture, but the same idea.

  5. It comes back later

    A few days on, we check that it still makes sense.

All 20 slices

Twenty slices, one tricky idea each

Most fraction trouble comes from a few perfectly sensible ideas that stop working with fractions. Each slice takes one of them apart.

Family I

Parts & Wholes

Equal shares of a whole, and what each number in a fraction is counting. Start here if fractions feel shaky: every other idea rests on these.

Family II

Fractions Have Size

Why 1/8 is smaller than 1/6, why 3/8 is less than 2/3, and how fractions live on the number line, including fractions greater than one.

Family III

Same Value, Different Forms

How 1/2 and 2/4 can be the same number, why simplifying never shrinks a fraction, and how to compare fractions by reasoning instead of guessing.

Family IV

Working With Fractions

Why we need common units to add and subtract, why multiplying can make a number smaller, and why dividing can make it bigger.

For parents

Homework help, without the rules you half remember

Every slice explains its idea in plain words for you, with things to say (and not say) and something to try at the kitchen table.

Read the parents’ guide

For teachers

Link straight to the misunderstanding

Every slice has its own address, a warm-up question, practice questions with answers and Common Core codes. Students can start from a link.

Read the teachers’ guide

Free account

There’s more with a free account

Every lesson works without one. With an account, your progress follows you to any device, and three extras open up.

  • Challenge rounds

    Five trickier questions on any slice, with fresh numbers every time you play.

  • Mixed practice

    Questions from different slices, shuffled together the way tests and real life mix them.

  • The Fraction Lab

    Build any two fractions and compare them as bars and points on a line, in same-size pieces.

Make a free account

A grown-up can set one up in about a minute.

Questions people ask

What is Slices?

A website for figuring out fractions, one idea at a time. Each slice is a short lesson about one thing that trips people up, like why (one eighth) is smaller than (one sixth). You make a guess, look at what it means, move the pieces around yourself, and then try something new.

Who is Slices for?

Kids around 8 to 12 who are meeting fractions at school, and the parents and teachers helping them. It works just as well for teenagers and adults who never quite felt at home with fractions. Plenty of grown-ups find out something new about (one half) ÷ (one fourth).

Is it free?

Yes. Every slice is free for everyone, and we keep it that way with donations rather than ads. You can start any lesson straight away, and your progress is saved on your device. A free account keeps that progress on every device and opens the extras: challenge rounds, mixed practice and the Fraction Lab’s comparison tools.

How is this different from worksheets or videos?

Worksheets ask for answers and videos explain. We start a step earlier, with the idea that’s getting in the way, such as “8 is bigger than 6, so (one eighth) must be bigger than (one sixth).” You test that idea yourself by changing the picture, then check it with new numbers and a different kind of picture.

How long does a slice take?

About three minutes. Nothing is timed, and you can go back over any step as many times as you like.

Is Slices safe for children?

Yes. There are no ads, no trackers, no chat and no public profiles, and children never have to share anything about themselves. Accounts are for grown-ups and teenagers 13 and older, so a parent can make one for the family.

Why we built it this way

We built Slices around a few things researchers have learned about fractions. Kids understand fractions better when they see them as numbers, each with a place on the number line. A lot of confusion comes from using whole-number rules where they don’t fit. And a well-chosen question shows what someone is really thinking.

Read why we made Slices