Maths Share has changed. Each fortnight you will receive a page of problems. There are 3 levels: mild, hot or spicy. Choose which level you’d like to have a go at and place your entry in the NEW entry box at the office! Two winners will be drawn out each week. Happy Maths Sharing!
THE HOT PROBLEM: A Bit of a Dicey Problem
Look at these two dice. If you add together the numbers of dots on them, the total is 2.
When you roll two ordinary six-faced dice like these and add together the two numbers, what results could you get?
Do you have more chance of getting one answer than any other? If so, what is that answer? And why?
What if you use a dice with 10 numbers on, like these?
What answers could you get now?
Do you have more chance of getting one answer than any other?
If so, what is that answer? And why?
Now try with more dice or a mixture of dice. What do you notice now?
1a You can roll numbers between 2 and 12 with two six-sided dice
b 7: Because you can roll combinations which use all the numbers on the dice.
1−6, 6−1, 5−2, 2−5, 4−3, 3−4
6 combinations give 7.
There are 36 possible combinations when you threw two six-sided dice SO 6 /36×100=16.67 % chance of rolling 7 with two six-sided dice.
2a With two ten-sided dice you can roll numbers between 2 and 20.
b 11; because there are ten combinations which give 11 which use all the numbers on the dice
There are are 100 possibilities when you roll two ten-sided dice.
So 10/100×100=10 % chance of rolling 11 with 2, 10 sided dice.