An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.
Find a great variety of ways of asking questions which make 8.
Choose any three by three square of dates on a calendar page.
Circle any number on the top row, put a line through the other
numbers that are in the same row and column as your circled number.
Repeat this for a number of your choice from the second row. You
should now have just one number left on the bottom row, circle it.
Find the total for the three numbers circled. Compare this total
with the number in the centre of the square. What do you find? Can
you explain why this happens?
The problem was "What is the sum of all the
digits in all the integers from one to one million?" and it was not
intended to be a long hard grind doing lots of adding up.
The very first solution of the month came from
Joshua from Russell Lower school in Ampthill, Beds. He took three
days to come up with a solution done the hard way. His method was
well thought out, and very clearly explained, and his answer was so
nearly correct that we even suspected a typo in the answer he gave.
No-one else sent in an answer as close as Joshua's.