Working systematically

In this addition each letter stands for a different digit, with S standing for 3. What is the value of YxO?

A Sudoku with clues as ratios or fractions.

Can you picture how to order the cards to reproduce Charlie's card trick for yourself?

Using the statements, can you work out how many of each type of rabbit there are in these pens?

An extra constraint means this Sudoku requires you to think in diagonals as well as horizontal and vertical lines and boxes of nine.

If you had any number of ordinary dice, what are the possible ways of making their totals 6? What would the product of the dice be each time?

I like to walk along the cracks of the paving stones, but not the outside edge of the path itself. How many different routes can you find for me to take?

Jack has nine tiles. He put them together to make a square so that two tiles of the same colour were not beside each other. Can you find another way to do it?

What do the digits in the number fifteen add up to? How many other numbers have digits with the same total but no zeros?

My cousin was 24 years old on Friday April 5th in 1974. On what day of the week was she born?