They can all be written in a pocket calculator using numbers and then turned down the numbers = those words. Please note the font in a pocket calculator is not the same as this computer, so whereas it works on a calculator it does not on this computer.
Hello = 07734 then turned upside down
Leslie = 317537 then turned upside down
Bell = 7739 then turned upside down
Is = 51 then turned upside down
His = 514 then turned upside down
Loose = 35007 then turned upside down