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Ages 8+ · Coding · Variables and data
Random numbers
How many times each number came up01234113203242546rolls
Bo's tally of twelve rolls.
The big ideaRandom means the next pick is a surprise. A computer can pick random numbers.

How it works

Random means a surprise: nobody can know the next one ahead of time.

Every card in the bag has the same chance, but one can come twice in a row.

Random is not tidy and does not take turns. Some numbers come up often, and one may never come up.

Computers can pick random numbers too, like shaking a bag of cards. Games use them for dice, shuffled cards and surprise treasure.

Random• rolling a dice• spinning a spinner• a card from a shaken bag• shuffling a pack of cardsNot random• counting one, two, three• the days of the week• a pattern that repeats• the steps of a recipe
Random, or not?

Example 1: Counting is not random

  1. Bo says, one, two, three, four, five, six.
  2. Everyone can guess the next number.
  3. That is just counting, and it is not random.

Example 2: A bag of cards

  1. Mina writes 1 to 6 on six paper cards and drops them in a bag.
  2. Bo shakes it, pulls a card, puts it back and shakes again.
  3. He gets a four, then a two, then a six, then a six again.
  4. Nobody could have known a six would come twice, and that is random.

Example 3: Reading a tally

  1. Bo rolls twelve times: 1 + 3 + 0 + 2 + 2 + 4 = 12.
  2. Six came up the most, four times, and three never came up.
  3. That is normal, because random is not tidy.
Bo's twelve rolls01234113203242546
Six came up four times; three never did.

Example 4: What could happen

  1. Bo shakes the bag of six cards and pulls one.
  2. It could be any of 1, 2, 3, 4, 5 or 6, even a six again.
  3. It cannot be a seven, because no card has a seven on it.

Words to know

random
A surprise: nobody can know the next one.
tally
A count of every roll.
chance
How likely each card is. Every card in the bag has the same.
pattern
Something that repeats, so you can know what comes next.

Watch out

Try it

  1. Is rolling a dice random?
  2. Is counting one, two, three random?
  3. Can a six come up twice in a row?
  4. The bag holds cards 1 to 6. Could Bo pull out a seven?
  5. In Bo's tally, six came up 4 times and two came up 3 times. How many times in all?
Answers: 1. Yes · 2. No · 3. Yes · 4. No · 5. 7
Try at homeWrite the numbers one to six on small papers and put them in a bag or a hat. Shake it, pull one out, write it down and put it back. Do this twenty times. Which number came up most? Did one never come? Is it the same as your grown-up's?
For grown-upsPlay the Mission: write the numbers one to six on small papers, put them in a bag or a hat, shake it, pull one out, write it down and put it back. Do this twenty times. Which number came up most? Did one never come? Is it the same as yours?
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