Shapes are added to other shapes. Can you see what is happening? What is the rule?
Jenny Murray describes how she developed her interest in making and breaking codes.
A number in a little box is put into a wonderful big box that adds something to the number and then a new number comes out at the end:
The first time this happens, 10 is put into the little box, so what happened in the big box to get the answer in the picture above?
Now three more boxes with new numbers in, go into the wonderful box one at a time. It still does the same as before.
So, what were these three new numbers that went in and do you have a better idea of what has been going on - remember it was the same for all four numbers that went in.
Imagine four new boxes now (with new numbers in) and the wonderful box does a new and different add or take away this time. For one of these boxes the number 10 was put in. The numbers that come out are these:
What could have happened? How did you work these out?
Discuss with others and see if there were different ways that you found the answers.
Once learners have had some time to work on the first part of the problem in pairs, ask them to share their ways of working with the whole group. Look out for those who give good reasons for choosing particular methods.
You may also like to draw attention to different methods of recording that you observe. Some children may have drawn pictures whereas others may have created calculations.