### Special Numbers

My two digit number is special because adding the sum of its digits to the product of its digits gives me my original number. What could my number be?

Think of a number... follow the machine's instructions. I know what your number is! Can you explain how I know?

### First Forward Into Logo 6: Variables and Procedures

Learn to write procedures and build them into Logo programs. Learn to use variables.

# Crossed Ends

##### Stage: 3 Challenge Level:

These crosses can be drawn on number grids of various sizes.

Add opposite pairs of orange numbers (i.e. north + south, east + west).
Notice anything? Try a few more.

Now try the same questions on crosses with two lines of symmetry, like these:

Experiment with grids of various sizes until you know that it's a coincidence, or until you know why it must always work. A sheet of number grids is available here

What happens if you add the orange squares in adjacent pairs? (try N + W, S + E )
Can you predict in advance how the totals will relate to each other?
What does it depend on?
Is it the same if you added them the other way round? (i.e. N + E, S + W)

Can you explain what you are finding?