I’ve taken accustomed to writing

2 + 3 = ___ or 2 + ___ = 5 and then later seamlessly transitioning to “2 + 3 = z, write down z:” or “2 + t = y, where y = 5. write down t:”

because it just seems so natural to identify these letters with natural things, such as numbers of beer bottles or cookies. kids typically giggle over these things because they think i’m making it up to be funny for their entertainment.