Interactive game. Set your own level of challenge, practise your table skills and beat your previous best score.
weekly problem 49 - 2013
The numbers 72, 8, 24, 10, 5, 45, 36, 15 are grouped in pairs so that each pair has the same product. Which number is paired with 10?
Charlie said: "It's Monday today, so it will be Monday again in $7$ days..
and in $770$ days...
and in $140$ days...
and in $35 035$ days...
and in $14 000 000 007$ days!" Alison said: "and it will be Wednesday in $2$ days...
and in $72$ days...
and in $702$ days...
and in $779$ days...
and in $14 777 002$ days!"
Do you agree with all of Charlie's and Alison's statements?
Charlie and Alison chose numbers that were easy to work with. Can you see why they were chosen?
Can you make up some similar statements of your own?
If today is Monday, what day will it be in $1000$ days' time?
Once you've had a go, have a look at how two students got started on this question:
Ann's Method:
Luke's Method:
Can you suggest any other methods for solving the problem?
Now try to suggest efficient methods to answer the following questions.
You could use mental strategies, pencil and paper, or calculator methods.