Working systematically

problem

Page Numbers

Age

7 to 11

Challenge level

1 out of 3

Exactly 195 digits have been used to number the pages in a book. How many pages does the book have?
problem

Broken Toaster

Age

7 to 11

Challenge level

1 out of 3

Only one side of a two-slice toaster is working. What is the quickest way to toast both sides of three slices of bread?
problem

Bunny Hop

Age

7 to 11

Challenge level

1 out of 3

What is the smallest number of jumps needed before the white rabbits and the grey rabbits can continue along their path?
problem

Crack the Code

Age

7 to 11

Challenge level

1 out of 3

The Zargoes use almost the same alphabet as English. What does this birthday message say?
problem

Two Dots

Age

7 to 11

Challenge level

1 out of 3

Place eight dots on this diagram, so that there are only two dots on each straight line and only two dots on each circle.
problem

Seating Arrangements

Age

7 to 11

Challenge level

1 out of 3

Sitting around a table are three girls and three boys. Use the clues to work out were each person is sitting.
problem

Knight's Swap

Age

7 to 11

Challenge level

1 out of 3

Swap the stars with the moons, using only knights' moves (as on a chess board). What is the smallest number of moves possible?
problem

Pasta Timing

Age

7 to 11

Challenge level

1 out of 3

Nina must cook some pasta for 15 minutes but she only has a 7-minute sand-timer and an 11-minute sand-timer. How can she use these timers to measure exactly 15 minutes?
problem

Fake Gold

Age

7 to 11

Challenge level

1 out of 3

A merchant brings four bars of gold to a jeweller. How can the jeweller use the scales just twice to identify the lighter, fake bar?
problem

Tri-Five

Age

7 to 11

Challenge level

1 out of 3

Find all the different shapes that can be made by joining five equilateral triangles edge to edge.