This is a whole class activity which develops tallying, estimating, fractions and probability!
It is uncomplicated and easy to set up. All KS2 pupils I have tried it with have enjoyed and progressed with it. I have usually asked pupils to make their estimations in pairs in order to promote Listening and Speaking skills.
Process – Place 12 counters/multilink into a sock. Have them in 3 different colours. The number of each colour can be to suit your purpose. (Do not let the pupils see you do this!)
Next, shake the sock and take a counter out. The pupils tally the colour, and the counter is replaced in the sock. Continue sampling the counters until you have a representative/fair sample.
Pupils then are told there are 12 counters in the sock and have to estimate how many of each colour there are. Points can be awarded for every colour correct.
The difficulty can be altered by changing the number of colours or the number of counters.