Use all the numbers 1, 2, 3 and 4.
Write one number in every circle.
The numbers joined by lines must have a difference of more than 1.
Now try this one. Use all the numbers 1, 2, 3, 4 and 5.
SOLUTIONS Differences (age 5 to 10) Reflections of these are also possible.
In the playground
A square playground is to be paved with slabs each 1 metre by 1 metre square.
Only whole slabs will be used.
The paving slabs have to be bought in packs of 50. Fifteen packs of slabs are needed to make sure that there are enough slabs.
What is the exact size of the playground?
SOLUTIONS Playground (age 9 to 14) The playground measures 27m x 27m.
Between 700 and 750 slabs will be used to pave the playground. 26 x 26 = 676, which is too few, and 28 x 28 = 784, which is too many. So the exact number of slabs needed must be 27 x 27 =729.