Lily's Ten Stones — Make a Ten to Add & Subtract
Help Lily the frog cross the pond on the number line: to add or subtract past ten, first hop to the golden Ten Stone, then the rest. Build the make-a-ten part yourself — 8 + 2 makes 10, then 10 + 4 is 14. A strategy game, not a speed drill. Common Core 1.OA.C.6.
Help Lily the frog cross the pond on the number line: to add or subtract past ten, first hop to the golden Ten Stone, then the rest. Build the make-a-ten part yourself — 8 + 2 makes 10, then 10 + 4 is 14. A strategy game, not a speed drill. Common Core 1.OA.C.6.
About this activity
Lily the frog crosses a pond on a number line by hopping to a golden Ten Stone first, then the rest of the way. To solve 8 + 6, the child builds the make-a-ten part — 8 + 2 makes 10 — and hops the remaining 4 to land on 14; for 13 − 4 she hops back to ten. This free, interactive Grade 1 math activity mixes addition and subtraction within 20 in the browser with no sign-up.
This is a strategy activity, not a speed drill. The make-a-ten strategy turns a hard fact into two easy ones by using ten as a friendly stopping point, and the child has to construct each step rather than just read an answer. Working out how much gets Lily to ten, then how far is left, builds the flexible thinking that makes mental addition and subtraction reliable.
It is aligned to Common Core 1.OA.C.6 — adding and subtracting within 20, using strategies such as making ten and decomposing a number to make a ten. No timer, no score — just calm, playful practice.
What's inside this activity
- Designed for Grade 1 learners (ages about 6–7)
- Common Core strand: Operations & Algebraic Thinking
- Aligned to Common Core standard 1.OA.C.6
How to play
Read the problem, like 8 + 6, and hop Lily to the golden Ten Stone first.
Build the make-a-ten part, then hop the rest of the way to land on the answer.
Not quite? Rebuild the hops and try again — there is no timer and no score.
What your child practices
- Making a ten as a first step to add or subtract past ten
- Finding how much is needed to reach the next ten
- Decomposing a number to subtract back to ten
- Using doubles and number relationships as helpful shortcuts
Learning goals
Add and subtract within 20 using make-a-ten strategies — the focus of Common Core 1.OA.C.6
Use ten as an anchor to break a hard fact into easy steps
Build the flexible mental-math thinking that fact fluency grows from
Frequently asked questions
- What does the Lily's Ten Stones — Make a Ten to Add & Subtract activity teach?
- Lily's Ten Stones — Make a Ten to Add & Subtract is a free interactive activity for Grade 1, focused on Operations & Algebraic Thinking. Children play it right in the browser — no printing, login, or setup required.
- Is Lily's Ten Stones — Make a Ten to Add & Subtract free to use?
- Yes. Lily's Ten Stones — Make a Ten to Add & Subtract is completely free, with no signup and no paywall, on any tablet, laptop, or classroom whiteboard.
- Which ages is this activity for?
- It is designed for Grade 1 (Operations & Algebraic Thinking) and works well for whole-class, small-group, or independent practice.