This collection of tasks is part of the activities for 14-16 year olds section of the Maths At Home feature. All you need to get started is a pencil and paper! The stars represent the challenge level, with three stars indicating the most challenging activities.
You may also wish to explore Just Jottings for 11-14 year olds, and Just Jottings for 16-18 year olds.

Slick summing
Watch the video to see how Charlie works out the sum. Can you adapt his method?

Ben's game

Two and two
How many solutions can you find to this sum? Each of the different letters stands for a different number.

Wipeout

Curvy areas

Negatively triangular
How many intersections do you expect from four straight lines ? Which three lines enclose a triangle with negative co-ordinates for every point ?