Numeracy Tutor Times

1) Brain Gym

2) Logic Riddles – choice of 3 arranged in increasing difficulty.

=94+10÷ 7 8x3Half of it ×3+5 -212

=18this30%

of this+ 5 + 9 ÷ 4 x1225%

of this

33

= 112thisX 5 Double itX 4 −80by ÷527

Brain Gym

2 18

2

Add % of it by

Logical Thinking 1 You keep all of your socks in one drawer. They are not arranged in pairs but all are singles. You only like two

colours though, so all of your socks are brown or black.

Just as you are about to open the drawer, there is a power cut and it is pitch black. You are running late for school and

need to find a pair!

What is the minimum number of socks that you need to take out of the drawer so that once you get into the light, you will

definitely have a pair?

Logical Thinking Puzzle 2 There are three bottles. They have been labelled

APPLE SQUASH, BLACKCURRANT SQUASH and APPLE AND BLACKCURRANT SQUASH.

However, the person who labelled the bottles put every label in the wrong place. You are allowed to

pick one bottle of squash to try the flavour. Which bottle do you choose to pick and why?

Blackcurrant Squash

Apple Squash

Apple &Blackcurrant

Squash

Logical Thinking Puzzle 3You have 9 coins which are identical to look at

with the naked eye. However, one of them weighs slightly less than the others.

What is the minimal number of weighing's you will need to do on the scales to guarantee that you can identify the coin which is lighter (and

explain how)?

Logical Thinking Answer 1

The answer is you must pick 3 socks.

There are only 2 different colours, therefore if you have 3 socks you will have either 1 black and 2 brown or 2 black and 1 brown.

Logical Thinking Answer 2

The answer is you must pick the mixed bottle (apple and blackcurrant).

If you pick the mixed bottle and it’s actually blackcurrant, then the bottle labelled blackcurrant must be apple and the bottle labelled apple must be mixed.

If you pick the mixed bottle and it’s actually apple, then the bottle labelled apple must be blackcurrant and the bottle labelled blackcurrant must be mixed.

Logical Thinking Answer 3

The answer is 2 weighing's. So you split the 9 coins into 3 groups of 3.   Weighing 1:  Choose two groups of 3 and put them on each end of the scale.  If one of the scales goes down then you know it is in that three.  If they balance, it has to be part of the 3 which are not on the scale Weighing 2:  You know it is one of the 3 coins.  Put 1 on each end of scale and leave 1 off.  If the scales balance then the heavier one is the one you left off the scale.  If the scales don’t balance, then it is the one which goes low on the scale