## How many addition signs needed to get the sum of 99 and two similar puzzles

How many addition signs are to be placed between the digits of number 987654321 to get a total of 99, and where should they be placed? Time limit 10 minutes. In part 2 and 3 of the puzzle, use digits 1 to 9 each only once to form numbers sum of which is 99. Part 2: how many ways can you do it? Part 3: find the number of ways this can be done using minimum number of addition signs. For the last two parts of the puzzle there is no time limit...