You can try to type the number 40 in a new layer and then use the layer mask to overlay into the previous layer.
Please have a look at the below tutorial.
Use the text tool set the font and siz you want. It can be change layer. Type 40 on the collage and cle the commit text check mark in the tool option bar. The will create a new text layer. That you can edit change size move style etc.
Thank you GautamBahl for your quick response. I'm much obliged. Off now to give it a try.
Thank you JJMack for your quick response. I'm much obliged. Off now to try this too.