Start at 81. Skip count by twos. What number is the arrow pointing at?
This problem asks us to skip count in twos. When we first learn to skip count in twos, we often start with zero. So we skip over the odd numbers and only say the even numbers: zero, two, four, six, eight, and so on. That’s why we often think that skip counting in twos is all about even numbers. But it’s not always the case.
Our question asks us to start on an odd number, 81. And so, to get from 81 to 83, we’ve skipped over an even number this time. We’re only saying the odd numbers: 81, 83. So let’s count through the odd numbers from 81 until we get to our arrow: 81, 83, 85, 87, 89, and 91.
So by starting on an odd number, we skip over all the even numbers and continue counting in odd numbers. And that’s how we know the number the arrow is pointing at is 91.