As a member of the last slide rule generation, I agree. The trusty slipstick was a calculation and thinking aid only. By not automatically handling units, for e

As a member of the last slide rule generation, I agree. The trusty slipstick was a calculation and thinking aid only. By not automatically handling units, for example, it forced you to think through the steps of your calculation. Back then students learned to approximate the result they were expecting. I wonder how my college students today have already estimated the total of their purchases when they arrive at the cashier. Such thinking doesn't seem to be part of the culture anymore.