Young Geniuses · Ages 13 to 14
Surds Speed Simplifier
Simplify surds and radicals against a friendly timer in a quantum energy research facility, for ages 13 to 14.
5 levels+40 XP
ProgressNot started
5 levels · BeginnerPlay
Young Geniuses · Ages 13 to 14
All Young Geniuses gamesNegative Index Reciprocal Drag
Match each negative index to the fraction it equals: 2 to the minus 3 is one eighth. For ages 13 to 14.
Drag dropNegative indices and their reciprocals~9 min per level5 levelsAll devices
- Free · no account required
- COPPA compliant
- +10 XP per level
- 5 levels
- Plays on all devices
- Curriculum-aligned
The learning journey
Every activity is one step. Here is where this one fits.
- Play(you are here)Learn the idea in a game
- PractiseLock it in on paper
- ReviewCome back and keep it sharp
- MasterTake on a harder challenge
- AchieveEarn a certificate
About Negative Index Reciprocal Drag
Negative Index Reciprocal Drag deals with one specific and extremely durable misconception. Asked what two to the minus three is, a large proportion of students answer minus eight, and the reasoning is entirely sensible: a minus sign in front of a number means negative, so a minus sign in the index should mean the answer is negative. Nothing they have been taught contradicts that until someone tells them it is wrong, and being told rarely dislodges it, because the reason it is wrong is never made clear. The reason is that the index is not describing the sign of the answer at all. A positive index says how many times to multiply by the base; a negative index says how many times to divide by it. Two to the three is one multiplied by two three times, which is eight; two to the minus three is one divided by two three times, which is one eighth. Nothing negative happens anywhere, and the answer is not merely positive but smaller than one, which is the opposite of what the misconception predicts. Matching a dozen powers to their reciprocals gets that across in a way that a stated rule does not, because the child produces the fraction themselves each time. Every answer on the board is a genuine reciprocal of one of the cards, so nothing can be placed by ruling out impossible values, and no two cards ever share an answer. Bases and indices grow with the level. Free, no sign-up, no advertising to children.
Where to go next
Chosen by the skills this activity practises.
Next — more of the same skill
Printable worksheets for this skill
A hand for grown-ups
- Before you start
- Find a calm few minutes with no rush. Let your child know it is fine to find some of it tricky — that is what practice is for.
- While they work
- Sit nearby but let them lead. If they get stuck, ask "what could you try?" rather than giving the answer — the thinking is the point.
- Afterwards
- Ask them to show you one they found easy and one they found hard. Praise the effort on the hard one, not just the right answers.
- Watch out for
- Rushing. If answers come too fast and wrong, slow the pace down together rather than pushing for more.
- Away from the screen
- Look for the same maths in everyday life — counting stairs, sharing snacks, spotting shapes on a walk.
How to play
A question appears on screen
A maths question is shown in large text at the centre of the play area. A timer bar begins counting down from 110 seconds.
Choose the correct answer
Answer options are shown as large buttons. Tap and drag, or use the mouse on desktop. Any input method works — touch, mouse or keyboard.
Build your streak
Each consecutive correct answer increases your streak. A longer streak lights up the flame icon and adds a bonus multiplier to the XP you earn for the level.
Finish the level
Each level has 5 questions. Complete them to earn the full level reward (+10 XP, plus up to +10 XP for a perfect run). Progress is saved locally and shown on the Parent Dashboard.
Curriculum alignment
Mapped to national curriculum frameworks so teachers and parents can match practice to school standards.
- United StatesCommon Core State Standards for Mathematics · algebra, divisionAligned to algebra, division number and operations objectives.
- United KingdomNational Curriculum for England — Maths · algebra, divisionAligned to algebra, division number and operations objectives.
- AustraliaAustralian Curriculum v9.0 — Mathematics · algebra, divisionAligned to algebra, division number and operations objectives.
- CanadaPan-Canadian Provincial Standards · algebra, divisionAligned to algebra, division number and operations objectives.
Common questions from parents & teachers
Everything you need to know before your child starts playing.
- Because a minus sign in front of a number means negative, so it seems it should mean the same in the index. Nothing they have met contradicts that until someone says so.
- How many times to divide by the base rather than multiply. Two to the minus three is one divided by two three times, which is one eighth.
- Because dividing repeatedly makes things smaller. That is the opposite of what the misconception predicts, which is what makes it worth seeing repeatedly.
- No. Every reciprocal on the board is distinct, so nothing can be matched by elimination.
More Young Geniuses games
View allSpeed Builder Young Geniuses · Ages 13 to 14
Tangent Line Builder
Read a curve and its tangent, then find the gradient at a point in an autonomous vehicle engineering lab, for ages 13 to 14.
4 levels+38 XPProgressNot started4 levels · BeginnerPlaySpinner Young Geniuses · Ages 13 to 14
Conditional Probability Spinner
Read probability trees and calculate conditional probabilities in a forensic investigation bureau, for ages 13 to 14.
3 levels+36 XPProgressNot started3 levels · BeginnerPlayPuzzle Young Geniuses · Ages 13 to 14
Circle Theorem Grid
Apply advanced circle theorems to fill a logic grid in the astronomical navigation archives, for ages 13 to 14.
4 levels+38 XPProgressNot started4 levels · BeginnerPlay