Have you noticed wording like this appearing?
“I also offer 121 coaching.”
I guess it’s people aiming to be cool; possibly in some cases a touch of laziness. But here’s what will happen in the reader’s head.
– interrupt reading
– call up number processing routines
– “They offer a hundred and twenty-one coaching sessions? That’s a lot! I wonder if that’s right…”
– whirr, click, arrival of puzzle-solving routines
– “Oh, you’re supposed to sound it out! One- two-one. OK, carry on.”
I put it to you that interrupting the flow of reading and requiring the reader to shift thinking modes might have its place in poster or advert design, but doesn’t belong in body text where you want a smooth flow of understanding. Use the proper version: “I also offer one-to-one coaching.”