This activity is good for helping pupils to work and talk together. It will encourage them to 'play' with $25$ objects and give reasons for choices.

After saying the riddle orally, you may wish to display it on a screen or have it written on a board so everyone can see. Allow pupils to choose whatever resources they think they'll need to try to find a solution and encourage discussion.

Tell me about your lines.

Children could find a variety of answers and create new problems that are similar for others to do.

Any help that will enable the pupil to talk openly would be good.