Hope someone can help

I have records of fuel inventory, and I've used yes/no switches for
the different types of fuel.

ie:        amount        gas    clear    dyed

        100        yes
        56            yes
        245                yes
        50        yes
ect.....

now I want totals of  the Gas, Clear, Dyed.

    So Total Gas = 150
        total Clear=56
                 total dyed=245

I've tried typing an expression in the query but nothing I try seems
to work :(

I know it must be simple, but I'm at a loss.

Can anyone help?

Thank You

Wally