Skip counting means counting in equal jumps — by 2s, 5s or 10s — instead of one at a time. Each jump adds a whole group at once, so you reach big numbers fast.

Press play: a marker hops along the number line in equal steps, a little school of fish appears for every jump, and we say each number we land on. Those landing numbers (2, 4, 6, \dots) are exactly the ones that make multiplication quick.

Khan Academy shows skip counting here: