TalentJR apps
4 is 2 × 2, so multiplying by 4 is the same as doubling and then doubling again. Doubling is easy, so even big × 4 sums become quick.
✓ You passed this trick’s test.
Double double — “n × 4 = n doubled, then doubled again”
Use it for: Any × 4 sum: legs on animals, wheels on cars, 4 sides of a square, and buying 4 of something.
Check: 23 × 4 = 20 × 4 + 3 × 4 = 80 + 12 = 92 ✓
Work it out in your head or on paper, type the answer and press Check. Stuck? Press “Show me how”.
Right: 0 · Tried: 0
20 questions. Check each answer, then go to the next one. Get 16 or more right to pass.
🏅 Sign in with Google to earn the ⚡ Double-Double Dynamo badge when you pass — and a certificate when you finish all 5 tricks of Part 1 · Finger & table tricks. You can still take the test without signing in.
Why does it work? When should you use it? Ask in English, मराठी or हिंदी.
Sign in with Google to ask Free — 20 questions a day.
Prefer a real teacher? TalentJR teachers take live online classes anywhere in India and visit homes in selected cities. Tell us what you need and our team will call you with timings and fees.