Summer Fun Number Sense Game for Numbers to 20

A Quick Number Sense Game for Numbers to 20

Looking for a low-prep math lesson that builds number sense, comparison skills, and mathematical thinking — while still feeling playful and engaging? This simple small-group activity is one of those easy-to-repeat games that works beautifully with learners working within numbers to 20.

You can use themed play mats like the Summer Math Play Mats from my Math Kit Bundle, or simply play directly on the table, desk, or a dry erase space. The magic is really in the mathematical conversation that happens during the game.

What You Need

• 20 counters for each student
• Number cards from 1–20

Optional supports:

• counting chart
• number line
• hundreds chart
• math wall visuals
• themed play mats

You can find the Summer Math Play Mats here!

How to Play

• Give each student 20 counters.
• Ask students to place any number of counters onto their mat or workspace. They choose the amount themselves.
• The teacher places down a number card between 1–20 at random.
• Together, work out which student’s collection is closest to the target number.

That’s it — simple setup, but so many opportunities for mathematical thinking.

Once students are confident, you can try:

• asking students to explain why they are closest
• having students order all collections from least to greatest
• introducing “exact match” bonus rounds
• comparing whose collection is furthest away
• recording differences using equations
• using teen numbers to explore place value language

Where the Real Learning Happens

This game is incredibly flexible because the strategies students use will depend on where they are in their mathematical development.

As the teacher, you can intentionally model and guide different strategies depending on student needs.

Some students may be:

• counting each collection carefully
• comparing which number is larger or smaller
• finding numbers on a number line or chart
• counting forward to the target number
• counting backward to find the difference
• recognising numbers instantly without counting
• beginning to think about “how far away” a number is

For example:

• “You have 12 and the target number is 15. How many more would you need?”
• “Who is closer — 9 or 17? How do you know?”
• “Can we use the number line to check?”

A counting chart or number line can make a huge difference here, especially for students still developing confidence with comparing numbers and understanding distance between numbers.

Why This Works So Well

One of my favourite things about games like this is how naturally they support differentiation.

Every student can access the task at their own level:

• some learners are still counting all
• others are comparing quantities visually
• some are beginning mental strategies and reasoning

Yet everyone is playing together and talking about the same mathematical idea.

Math play creates opportunities for:

• meaningful discussion
• low-pressure practice
• mathematical language development
• confidence building
• flexible thinking

And when you add engaging themes or hands-on materials, students are often far more willing to persist and participate.