Ordering numbers and adding in any order

Order from least to greatest: 18, 8, 81, 108, 80.

Order from greatest to least: 346, 364, 634, 436.

Write three numbers that are greater than 200 and less than 300. Order them.

Solve and swap: 14 + 4 and 9 + 15.

Find the missing number: 12 + 8 = ? + 12.