A Secret about Citrus Circles

by Laura Overdeck

It’s Pi Day, 3/14, the day we celebrate a very special number. When you multiply the width of a circle by “pi” (3.14159265…), you get the distance around its edge! So today we can also celebrate our favorite circle-shaped foods, like the glowing oranges, lemons and limes in this photo. If you slice across any citrus fruit, you’ll see a circle divided into sections called “liths.” How many liths does an orange or lemon have? Turns out there’s no exact number. Most lemons have 8 or 9 segments; oranges and limes can have up to 12; and grapefruit can have 14 or even more. And you can figure out the number before cutting the fruit — read on to learn the trick!

Wee ones: How many full orange circles can you see in the picture? Count as many as you can!

Little kids: Which has more sections, a 10-lith lime or an 8-lith lemon? Bonus: If your orange has 12 cute little sections, and 4 of them have seeds you have to spit out, how many don’t?

Big kids: SECRET: If you pull that bellybutton thing off a citrus fruit and count the little white dots under it, it tells how many sections the fruit has! If each of your 2 grapefruits have 14 dots, how many liths do they have together?  Bonus: If your pile of 9-segment lemons and 14-segment grapefruit has 51 sections in total, how many of each fruit must you have?

Wee ones: We count 3 big orange circles.

Little kids: The lime.  Bonus: 8 seed-free sections.

Big kids: 28 liths.  Bonus: 3 grapefruit and 1 lemon. If you keep subtracting 9 from 51, the only result that is divisible by 14 is 42 (51 minus 9).

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