GCHQ Number puzzles

Are you code breaking levels of number wangery?

http://www.bbc.co.uk/programmes/articles/5wkxjTtqRvq8Cyrrjxtk7tc/puzzle-for-today

I will copy and paste the puzzles into this thread as they get published.

  Quote

Puzzle 1.

Take the digits 1,2,3 up to 9 in numerical order and put either a plus sign or a minus sign or neither between the digits to make a sum that adds up to 100. For example, one way of achieving this is: 1 + 2 + 34 - 5 + 67 - 8 + 9 = 100, which uses six plusses and minuses. What is the fewest number of plusses and minuses you need to do this?

I can do it in 4.

My answer so far

3

edit: solution is on the page now anyway hurk

nice thread