Skip counting by 10s

Ten is the only skip-counting jump that lands in the exact same column every single time: add ten to any number and the tens digit moves while the ones digit stays put, so the shaded cells stack straight down the grid's right edge instead of stepping sideways or tracing a diagonal. A child doesn't have to search the page for the rule — they can see the whole pattern in one glance, which is exactly why by-10s is where skip counting usually starts.

That single column is also the clearest place-value moment on the entire chart: reading down it is reading 10, 20, 30 all the way to 100 — ten tens, made visible as one straight line rather than a fact to memorise. Once that reads as obvious, the diagonal that multiples of nine trace across the same size grid is a much smaller leap.