I haven't messed with binary since college. (Well, some bitmask stuff happens every half decade I guess.)
If you remember binary is just base2 I bet you could do it. Since you do accounting stuff, could you split a number into each base 10 component? 462 = (400,60,2). A bit of thinking leads me to 10^i, a for loop and some conditional subtraction / modulo. Binary is just 2^i.
My point was, it wasn't from memory and because any mistakes I make are very painful and tedious to repair my first instinct is to Google things to double check everything before taking action.
So, no, I'm going to refuse a screen that prevents me from solving it the way I'd solve other problems I don't do regularly.
If you remember binary is just base2 I bet you could do it. Since you do accounting stuff, could you split a number into each base 10 component? 462 = (400,60,2). A bit of thinking leads me to 10^i, a for loop and some conditional subtraction / modulo. Binary is just 2^i.