For what value of x is angle ABC - angle DEF?

Using only the digits 5, 6, 7, 8, how many different three digit numbers can be formed if no digit is repeated in a number?

When steve woke up. his temperature was 102 degrees f. two hours later it was 3 degrees lower. what was his temperature then?

During how many months was the difference between the number of days with homework and with no homework greater than 6?