Free interactive math game: Skip Counting — By 2, 5, 10. Part of the Learning Numbers category on MathKite.
Taken from the generator that powers this exercise. A fresh set appears every time the page is opened, and the printable worksheet holds ten of them.
Recognizing a counting pattern and continuing it — the groundwork for multiplication tables.
Take two numbers that sit next to each other in the sequence and subtract to find the step. Then apply that step to the number beside the gap.
In 15, ?, 25 the two known values are ten apart across two steps, so each step is 5 and the missing number is 15 + 5 = 20.
Adding the step to the wrong neighbor. Check the answer against both sides of the gap — it should fit going forwards and backwards.