How to: Quickly typing a single letter/number/symbol on iOS

This video demonstrates how to quickly type a single number/symbol whilst typing mostly text, as well as how to quickly type a single letter whilst typing mostly numbers/symbols. With this trick, unnecessary taps on the 'ABC/123' toggle to swap between 'qwerty' and 'number/symbol' keyboard layouts are eliminated, making typing smoother and quicker.
Beyond the 'ABC/123' toggle, this trick also applies as well to the 'CAPS' toggle.