Im trying to enter a formula that calculates a starting value in currency in one cell, and calculates the difference between a second cell with a finishing value . I.e [a1]£100 [b1]150 [c1]+50
[b2]150 [b2]120 [c2]-30
the reason im struggling is its not a simple + or -, and i dont know the statements that controls if its a plus or a minus. For example i tried, and this and i didnt work
=if(a1<b1),then(a1-b1),else(a1+b1)
i dont even think excel recognises else, 
Anyone know a simpler way of calculating the profit or loss from two money values. I'e googled loads with no luck. Thanks.
[b2]150 [b2]120 [c2]-30
the reason im struggling is its not a simple + or -, and i dont know the statements that controls if its a plus or a minus. For example i tried, and this and i didnt work
=if(a1<b1),then(a1-b1),else(a1+b1)


Anyone know a simpler way of calculating the profit or loss from two money values. I'e googled loads with no luck. Thanks.