Struggling with the If statement

I have a column with numbers both negative and positive. Now i want to add a column that states 'negative' whenever a number is below 0 and 'positive' whenever its above. My formula is if([Transactiebedrag]=<0) then ([Transactiebedrag]= "negative") else ([Transactiebedrag]= "positive") . I keep getting an error where its expecting a token literal. Can anyone help me optimise the formula?