Mental Mondays #21

Here's a versatile idea that helps children use and apply their knowledge of fractions or percentages in a surprisingly fun way. You begin by showing the children something that appears to be a word puzzle, but actually contains some covert mathematics.

However, the puzzle you show them is only the beginning. The real fun (and the real maths) begins to unfold when the children start creating their own similar puzzles.

Here's how it could start:

Tell the children they are looking for "a large bird of prey" hidden in the following information

66% TEA
40% GLASS
33% EYE

A gentle clue could be to get the children to look at the number of letters. Both 'tea' and 'ey' contain 3 letters so 33% and 66% could be indicating one or two letters of those particular words. 40% of a five letter word would have to be 2 letters. Therefore, the full solution would be:

66% TEA
40% GLASS
33% EYE

"a large bird of prey" = EAGLE

If appropriate, you could start the children off with an easier set of clues:

Here, we are looking for "liquid ice" (very easy):

1/3 RAW
3/4 GATE
1/4 FOUR

Clearly, fractions and decimals are interchangeable. The puzzle could also be made more complex by using equivalent fractions - 5/15 RAW or 12/16 GATE, for example.

The solution is:

1/3 RAW
3/4 GATE
1/4 FOUR

"liquid ice" = WATER

At this point the children should be able to work together to create their own. The focus is (of course) on the accurate use of fractions or percentages, but the language element means that it is easy to draw out cross curricular links. Maybe with a focus on 'topic' words from recent geographical or historical work, for example. Here, children used a book of place-names together with their maths skills to invent puzzles involving capital cities, the clues to which had to be UK town names!

25% LEEK + 25% KINGSTON + 40% DOVER + 10% NAILSWORTH = ?

2/8 PAIGNTON + 4/10 RIPON + 1/5 GRAYS = ?

[scroll down for answers]

A further thought is to focus on some apt, semi-poetic word choices - here are a couple of our favourite ideas linked to Olympic events, can you guess the appropriate sport?

1/4 HORRIBLE + 2/5 STICK + 1/4 KNEE + 1/6 INJURY = ?

50% HARD + 20% METAL + 2/5 MEETS + 1/3 AIR = ?

[scroll down for answers]

ANSWERS

25% LEEK + 25% KINGSTON + 40% DOVER + 10% NAILSWORTH = LONDON

2/8 PAIGNTON + 4/10 RIPON + 1/5 GRAYS = PARIS

1/4 HORRIBLE + 2/5 STICK + 1/4 KNEE + 1/6 INJURY = HOCKEY

50% HARD + 20% METAL + 2/5 MEETS + 1/3 AIR = HAMMER