Does anyone travel with a pocket calculator?

I keep thinking about all the street vendors who give me weird looks when I don’t speak their language, wouldn’t it be better than handing over my phone just having a calculator on hand or am I just over complicating things and just always have numbers ready on my phone like if I wanted 2 x (Price) just type that in and hand phone over? I’m usually talking about for market/street sellers I’m thinking about doing like SEA mostly next 6 months.

Im usually just using Google Translate to translate the menu from whatever language its in and they usually don’t also speak English.

Thanks!