Défi des Nombres: a number target game for sharper arithmetic

Défi des Nombres is a number target game for Android in which you receive five numbers and a target, then combine them with the four operations to hit the target exactly. It suits students from grade 4 (CM1) to grade 9 (3ème), and adults too.

Every grid has at least one solution, and a stuck player can skip and see one. The game is a compact way to practise exact calculation, a habit that experiments reward.

Your first round, step by step

1. Install the app from Google Play and read the short animated tutorial.
2. Pick a level: easy, medium, hard or expert.
3. Tap a number, an operation, then a second number; the result appears and can be reused.
4. Keep going until the result equals the target, using each starting number only once.
5. Skip the grid if you are stuck and study the solution shown.

What you will find inside the number target game

• Five numbers and one target per grid, with a solution always available.
• A scoring scale: 1 point for addition or subtraction, 2 for multiplication, 3 for division.
• A 13-point bonus when all four operations appear in one calculation.
• Ten grids per round, up to 130 points.
• Target ranges from 10 to 40 on easy up to 60 to 300 on expert.
• Timed challenges: a 60-second sprint, a 3-minute marathon and a survival mode.
• Six ranks, 12 badges, streaks and a history of your calculations.

The store text describes the app in French and English. It does not mention any account or saving feature, so check this on your own device.

Who it is for

Primary and middle school students use the game to revisit multiplication tables and exact division. Parents and teachers can play along, because the rules fit in one sentence.

The reward for division is the interesting design choice. Dividing exactly forces you to think about factors, which is the same reasoning used to simplify units or ratios in a physics problem.

Why scientists like a number target game

In a lab report you often combine measured values with several operations, and planning the order of steps saves time. Playing with targets trains that planning in miniature.

Pair it with the AP Physics 1 worksheets on our site: after a few rounds you will notice that estimating the result before pressing the calculator catches many input errors.

A short training plan for the four levels

Start on the easy level, where targets lie between 10 and 40, until you solve most grids without skipping. Then move to medium, with targets from 20 to 60, and look for products that land close to the target.

On hard and expert, targets reach 120 and 300, so a single multiplication rarely works. You need two or three steps, and the order matters. That is excellent practice for any multi-step calculation.

Finish each session with the 60-second sprint. The score is easy to compare from day to day, and it shows whether your speed improves without lowering accuracy.

Tips for better scores

• Look for the target’s factors first; a product often gets you close in one move.
• Use division only when a clean quotient is visible, since it pays the most.
• Try for the all-operations bonus on easy grids, where small numbers leave room to experiment.
• Replay the sprint mode weekly and compare your best score.

Frequently asked questions

What is Défi des Nombres?

Défi des Nombres is an Android mental math game. You get five numbers and a target, and you chain additions, subtractions, multiplications and divisions to reach the target exactly, using each number once.

Can every grid be solved?

Yes. The description states the target is always reachable, so a solution exists in every grid. If you are blocked, you can skip the grid and the game shows one possible solution.

How is the score calculated?

Addition and subtraction earn 1 point, multiplication 2 points and division 3 points. Using all four operations in a single calculation gives a 13-point bonus. A round of ten grids can reach 130 points.

Which ages is it designed for?

The description targets students from grade 4 (CM1) to grade 9 (3ème), but also parents, teachers and anyone who wants to keep a quick mind. Four difficulty levels let beginners and experts both find a fit.