Sending Cards
There are 20 pupils in the classroom.
For Christmas, they decided to send each other greeting cards.
How many cards will be given out in total?
For Christmas, they decided to send each other greeting cards.
How many cards will be given out in total?
Download a paper version at the bottom of the page.
Challenging Version
There are 20 pupils in the classroom, 8 of whom have email addresses.
At Christmas, those without email addresses will give a card to everyone, including those with email addresses.
There are 20 pupils in the classroom, 8 of whom have email addresses.
At Christmas, those without email addresses will give a card to everyone, including those with email addresses.
Those with email addresses will send each other virtual Christmas cards and physical cards to those without email addresses.
In total, how many physical cards will be given in this class?
In total, how many physical cards will be given in this class?
Download a paper version at the bottom of the page.
380 cards!
Each pupil will send a card to everyone but him/herself, so it will be 19×20 instead of 20×20.
324 cards!
Each pupils that has an email address – so 8 – will send a physical card to the others whom doesn’t (so 12)
Then the 12 will send to each pupil a card but her/himself so 19 cards
8×12 + 12×19 = 324
To Print
Riddle
Challenging Riddle
What’s the Maths behind?
What’s behind? Maths tips
The participants developed their numeracy and problem-solving skills.
