Write an algebraic expression to model the unknown number situation. the difference of a number and seven Subtraction Words Which statements are true? Select all that apply. You can replace "a number" with a variable to represent an unknown value. You can replace "difference" with a division sign. You can replace "difference with a subtraction sign. You can replace "seven" with 7. The correct expression is n-7. O The correct expression is 7-n. decreased by difference fewer less than subtract