Addition and subtraction

Can you go through this maze so that the numbers you pass add to exactly 100?

Use the 'double-3 down' dominoes to make a square so that each side has eight dots.

In a square in which the houses are evenly spaced, numbers 3 and 10 are opposite each other. What is the smallest and what is the largest possible number of houses in the square?

There are 78 prisoners in a square cell block of twelve cells. The clever prison warder arranged them so there were 25 along each wall of the prison block. How did he do it?

Find at least one way to put in some operation signs to make these digits come to 100.

Amy has a box containing domino pieces but she does not think it is a complete set. Which of her domino pieces are missing?

Katie had a pack of 20 cards numbered from 1 to 20. She arranged the cards into 6 unequal piles where each pile added to the same total. What was the total and how could this be done?

Mrs Morgan, the class's teacher, pinned numbers onto the backs of three children. Use the information to find out what the three numbers were.

Choose four different digits from 1-9 and put one in each box so that the resulting four two-digit numbers add to a total of 100.

Can you make square numbers by adding two prime numbers together?