Math puzzles!

Little bit of trying around Excel:

2) 98-76+54+3+21 (thought it was just + or - signs, what Jon did was cheating sorta).

Yeah, I thought about it while afk after I posted it and remembered it was supposed to be +/-. :/ I'll do a legit one, here:

2) 98-7+6-5+4+3+2-1


3) 219 438 657
4) I don't understand what I'm trying to achieve here. Ah. After Googling, an image of the equation cleared it up for me. But the page also gave the answer away.