Line the numbers up so ones sit under ones and tens under tens. Always start at the RIGHT (the ones) and move left. Add 47 + 38. First the ones: 7 + 8 = 15 — write the 5, carry the 1.

  ¹
  4 7
+ 3 8
-----
    5

Then the tens: 4 + 3 = 7, plus the carried 1 = 8.

  ¹
  4 7
+ 3 8
-----
  8 5

Subtracting is the same, but you BORROW when the top digit is too small. Take 52 − 37. The ones say 2 − 7 — too small, so borrow 1 ten: 12 − 7 = 5. The tens are now 4 − 3 = 1.

  5 2
- 3 7
-----
  1 5

Line them up, start at the ones, carry when adding and borrow when subtracting.