(b + a) - a = b

Start from the conclusion and work back up the proof. Click the arrow to show the parents.

• (b + a) - a = b,

  if the following are true:

  • a = b
  • b = c

  then a = c

  • b + (a - a) = b,

    if the following are true:

    • a = b
    • b = c

    then a = c

    • b + 0 = b, a + 0 = a
    • b + (a - a) = b + 0,

      if a = b, then x + a = x + b

      • a - a = 0, a - a = 0
  • (b + a) - a = b + (a - a), (a + b) - c = a + (b - c)