Working systematically

Replace the letters with numbers to make the addition work out correctly. R E A D + T H I S = P A G E

Can you substitute numbers for the letters in these sums?

This problem is based on a code using two different prime numbers less than 10. You'll need to multiply them together and shift the alphabet forwards by the result. Can you decipher the code?

Suppose you are a bellringer. Can you find the changes so that, starting and ending with a round, all the 24 possible permutations are rung once each and only once?

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

Can you find squares within a number grid whose entries add up to an even total?

Can you make the numbers around each face of this solid add up to the same total?

How many numbers do you need to remove to avoid making a perfect square?

Alberta won't reveal her age. Can you work it out from these clues?

Can you find a number and its double using the digits $1$ to $9$ only once each?