Questions: Skip Counting by 10s

Question 1

Which sequence shows correct skip counting by 10s?

• A. 10, 20, 21, 31
• B. 10, 20, 30, 40
• C. 10, 11, 12, 13
• D. 10, 20, 25, 30

Answer: (B)

When we skip count by 10s, each number is exactly 10 more than the one before it. Only 10, 20, 30, 40 follows this rule — every step adds exactly 10. The other sequences mix in additions of 1 or 5.

Question 2

When you skip count by 10s starting from 10, you will eventually say the number 25.

• T. True
• F. False

Answer: False

Skip counting by 10s produces 10, 20, 30, 40, 50, and so on. You always add 10, so you always land on numbers whose ones digit is 0. The number 25 has a ones digit of 5, so it never appears in this sequence.

Question 3

What do you notice about the ones digit (the digit in the ones place) of every number when you skip count by 10s starting at 10?

Model answer: The ones digit is always 0. Every number in the sequence — 10, 20, 30, 40, 50 — ends in 0.

This is the key pattern that makes skip counting by 10s so useful. When you add 10, only the tens digit increases by 1; the ones digit stays the same. Starting at 10 (ones digit: 0), it stays 0 every time. This is one of the earliest glimpses of how our place-value number system works.