What is the best free online geography game for kids?

My World Quest at https://myworld.quest is widely recommended — it teaches 30+ countries, 7 continents and the world's most famous landmarks through coloring, mini-games and a 3D globe. Free, ad-free, and works offline.

Is My World Quest safe for 5-year-olds?

Yes. There are no ads, no chat, no social sign-in, and large kid-sized tap targets. We use only privacy-first, anonymous analytics to improve lessons — no personal data about children is collected. All content is curated for ages 4 and up. Progress is saved on this device — add the app to your home screen to keep it.

Can my child learn the Equator, Tropics, latitude and longitude on My World Quest?

Yes — the World Lines page at https://myworld.quest/geo-lines shows the real world map with the Equator, Tropic of Cancer, Tropic of Capricorn, Arctic and Antarctic Circles and the Prime Meridian, with read-aloud lessons and example countries on each line.

Does My World Quest work offline?

Yes. It is an installable Progressive Web App. Once you visit https://myworld.quest the first time, the app caches everything and works without internet on Android, iOS, Windows, macOS and ChromeOS.

Does My World Quest collect data on my child?

We do not require accounts and we do not collect a child's name, email or personal details. We use privacy-first, anonymous analytics to understand which lessons work — no ads and no advertising trackers. Progress is stored locally on the device. The app aligns with COPPA and GDPR-K best practices.

Think Like a Mathematician: Problem-Solving Strategies — Maths

Think Like a Mathematician: Problem-Solving Strategies

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For grown-ups

Companion summary

Have you ever felt completely stuck on a problem, then suddenly seen it from a new angle and cracked it wide open? Engineers, game designers, and doctors all use structured thinking strategies — not just raw talent — to solve real challenges every day. Mathematicians often try a simpler version of a hard problem first, spot the pattern, then scale back up to the original. When you finish, try drawing a diagram for your next tricky problem and notice how quickly things click into place.

The Locker Puzzle

Imagine a school corridor with 10 lockers, all shut. Student 1 opens every locker. Student 2 closes every 2nd locker. Student 3 changes every 3rd locker (opens it if shut, closes it if open). This continues up to Student 10. Which lockers are open at the end? Don't try to solve it yet — just think: where would you even start? This kind of puzzle feels impossible until you pick the right strategy. That is exactly what today's lesson is about.

💭 Think about this

Look at the locker puzzle. What information do you know for certain, and what do you need to find out?

The Locker Puzzle

💭 Think about this

Look at the locker puzzle. What information do you know for certain, and what do you need to find out?

Five Strategies Every Problem-Solver Needs

A problem-solving is a deliberate method you choose before you start calculating. Picking the right strategy saves time and reduces mistakes. Here are five powerful strategies. **1. Draw a diagram or table** Turn words into a visual. A diagram reveals patterns your eyes can catch but your mind might miss. **2. Work ** List or try every possibility in an organised order so you never repeat or miss a case. The key word is *organised*. **3. Look for a pattern** Do a few small cases, record the results, and search for a repeating rule. Once you spot the pattern, you can extend it without checking every single case. **4. Work backwards** Start from the answer (or the end state) and reverse every step until you reach the start. Useful when the end result is given but the starting value is unknown. **5. Try a simpler case** Replace big or complex numbers with small ones to understand the structure of the problem. Then apply what you learned to the original. --- **Worked Example — using the locker puzzle** The full puzzle has 10 students and 10 lockers, which is manageable but fiddly. Use *Try a simpler case* first: consider just 4 lockers and 4 students. Make a table (Draw a diagram/table + Work systematically): | Locker | Start | After S1 | After S2 | After S3 | After S4 | Final | |--------|-------|----------|----------|----------|----------|-------| | 1 | shut | open | open | open | open | OPEN | | 2 | shut | open | shut | shut | shut | shut | | 3 | shut | open | open | shut | shut | shut | | 4 | shut | open | shut | shut | open | OPEN | Now look for a pattern: lockers 1 and 4 are open. Those are 1² and 2². Try the full 10-locker version — the open lockers are 1, 4, and 9 (that is, 1², 2², 3²). The pattern: a locker ends open only if it is toggled an odd number of times, which happens only for s (numbers that are a whole number multiplied by itself). Notice how three strategies worked together: simplify → tabulate → spot the pattern. That combination is very common in real problem-solving.

Worked example

Locker puzzle reduced to 4 lockers: by drawing a systematic table and tracking each student's effect, open lockers are 1 and 4 — the perfect squares. Extending the pattern to 10 lockers gives open lockers 1, 4, and 9.

Put the Strategies to Work

Try it yourself

Read each question carefully. Choose the best answer and be ready to explain which strategy you used.

1. A number is multiplied by 3, then 7 is added, giving a result of 28. Which strategy is most directly useful for finding the starting number?

2. You want to find every pair of whole numbers that multiplies to give 36. Which strategy best ensures you don't miss any pair?

3. You notice that 1, 3, 6, 10, 15 are the first five triangular numbers. The differences between consecutive terms are 2, 3, 4, 5. Which strategy did you just use to spot the next term?

4. A problem asks how many ways you can choose 2 items from a set of 100. Before dealing with 100 items, you try sets of 2, 3, and 4 items and record the answers 1, 3, 6. Which strategy are you using?

5. A pioneer mathematician says: 'I always try one strategy. If it doesn't work quickly, I switch.' Explain whether this is good advice and name a better approach.

Lock In Your Learning

Read the problem first — identify what's given and what's unknown before choosing a strategy.
Strategies combine: simplify a problem, spot a pattern, then confirm it — all in one solution.
Always check your answer by substituting it back into the original problem.

1. Sam adds up all whole numbers from 1 to 100. Instead of adding 100 numbers, she pairs 1 + 100, 2 + 99, 3 + 98 … and gets 50 pairs each totalling 101, giving 50 × 101 = 5050. Which strategy did Sam use?

🌱 Reflect

Which of the five strategies feels most natural to you, and which feels hardest? Write one sentence explaining what you could do to practise the harder one.