Mathematics - Pre-Algebra - Evaluating expressions - Plug and Play

Show expression '2x + 1'. 'If x = 3, what does this expression equal?' Options: 5, 6, 7, 8. Quick substitution problems. Do 5 rounds with simple expressions (x+4, 3x, 2x-1, x², 10-x) and given values. The student practices the mental process of 'replacing the letter with the number'.