Odd and even numbers

problem

One of Thirty-Six

Age

5 to 7

Challenge level

Can you find the chosen number from the grid using the clues?
game

Odds and Threes

Age

7 to 11

Challenge level

A game for 2 people using a pack of cards. Turn over 2 cards and try to make an odd number or a multiple of 3.
game

Down to Nothing

Age

7 to 11

Challenge level

A game for 2 or more people. Starting with 100, subratct a number from 1 to 9 from the total. You score for making an odd number, a number ending in 0 or a multiple of 6.
problem

Number Tracks

Age

7 to 11

Challenge level

Ben's class were cutting up number tracks. First they cut them into twos and added up the numbers on each piece. What patterns could they see?
problem

Arrangements

Age

7 to 11

Challenge level

Is it possible to place 2 counters on the 3 by 3 grid so that there is an even number of counters in every row and every column? How about if you have 3 counters or 4 counters or....?
problem

Three Spinners

Age

7 to 11

Challenge level

These red, yellow and blue spinners were each spun 45 times in total. Can you work out which numbers are on each spinner?
problem

Diagonal Trace

Age

7 to 11

Challenge level

You can trace over all of the diagonals of a pentagon without lifting your pencil and without going over any more than once. Can the same thing be done with a hexagon or with a heptagon?
problem

Sets of Numbers

Age

7 to 11

Challenge level

How many different sets of numbers with at least four members can you find in the numbers in this box?
problem

Sets of Four Numbers

Age

7 to 11

Challenge level

There are ten children in Becky's group. Can you find a set of numbers for each of them? Are there any other sets?
problem

Crossings

Age

7 to 11

Challenge level

In this problem we are looking at sets of parallel sticks that cross each other. What is the least number of crossings you can make? And the greatest?