How can i strikethrough only one word or number in a text block?

I’m having a problem trying to do a strikethrough on one number in my text block. The text block says “$39.99 USD $19.99 USD”, and I want the “$39.99 USD” to have a strikethrough through it. When I do a strikethrough, it does it to the whole text block.

You can separate them into 2 elements, or apply a span to just the first price and strikethrough that span’s class.