Dinner time is the perfect time for conversations and a great opportunity to engage with your children. The idea of Dinner Time Maths is to add a small spark of maths to the conversation. Discuss a mathematical idea as a family or solve a problem together.

Here are some fun maths facts to spark interesting conversation over the dinner table.

  • If you write out pi to two decimal places, backwards it spells “pie”. Next time you serve up some apple pie at dinner, tell your kids this great little tidbit! It may even help them to remember pi to 2 decimal places.

  • A pizza that has radius “z” and height “a” has volume Pi × z × z × a. Because the area of a circle is Pi multiplied by the radius squared (which can be written out as Pi × z × z). Then you multiply by the height to get the total volume. We love this one and it’s another great one for dinner time! This may help them to never forget the formula for the volume of a cylinder. 🙂

Pizza .! ♥

Photo credit: Ashley Linh Trann ♥ / Foter / CC BY

  • 111,111,111 × 111,111,111 = 12,345,678,987,654,321. Notice how the numbers go from 1-9 and then back down again? It also works for smaller numbers: 111 × 111 = 12321.

  • Zero is the only number that can’t be represented in Roman numerals. The Latin word “nulla” would have been used instead.

  • Cicadas use prime numbers as an evolutionary strategy. Cicadas incubate underground for long periods of time – 13 or 17 years – before coming out to mate. 13 and 17 are both prime numbers. It’s thought cicadas ended up in these prime number life-cycles because it meant they came into contact with predators on more round numbered life-cycles less often.

Diemeniana frenchiPhoto credit: Foter / GNU Free Documentation License

  • 10! means 10 factorial. 10! = 10 × 9 × 8 × 7 × 6 × 5 × 4 × 3 × 2 × 1 = 3628800 seconds. Which is 42 days, or 6 weeks, exactly.

  • The number 5 is pronounced as ‘Ha’ in Thai language.555 is also used by some as slang for ‘HaHaHa’.The three gigglersPhoto credit: Alan Cleaver / Foter / CC BY

  • Googol (meaning & origin of Google brand ) is the term used for a number 1 followed by 100 zeros and that it was used by a nine-year old, Milton Sirotta, in 1940. The name of the popular search engine ‘Google’ came from a misspelling of the word ‘googol’.

  • Have you ever noticed that the opposite sides a die always add up to seven (7)?

6sided dicePhoto credit: Foter / CC BY-SA

  • Among all shapes with the same perimeter a circle has the largest area.  Among all shapes with the same area circle has the shortest perimeter .

  • Inner CirclePhoto credit: jronaldlee / Foter / CC BY

These are some of our favourites. For more fun maths facts check out this BuzzFeed article and this MakeMeGenius page.