Seventeen horses
Concepts | Instruction, use of language |
---|---|
KS3 curriculum | 3.3d, 3.3e |
KS4 curriculum | 3.3e |
Resources
Teaching notes
When presenting this puzzle, using the PowerPoint version has the advantage of telling the story a bit at a time. This means that you can ask the students to suggest possible solutions to the problem before the executor’s idea is revealed.
Students need to understand that the only reason that the executor added his horse into the equation was because 17 cannot be divided by 2, 3 or 9, whereas 18 can. This can be illustrated using fractions:
1/2 + 1/3 + 1/9 | |
= | 9/18 + 6/18 + 2/18 |
= | 17/18 |
This also shows that if one of the horses had not died, the executor would have had the dilemma of having an extra horse left over!
Extension
Ask students to write a short story illustrating something they have learnt recently in another subject.