Mental maths sprint, Class 1 to 10

Mental arithmetic is not the same skill at six and at sixteen. A Class 1 child working out 8 + 5 is bridging across ten for the first time - a genuinely new idea. A Class 9 child working out 15% of 220 is applying something they already understand, at speed. Both are “mental maths”, and a tool that asks the same kind of question of both children is not respecting either of them. That is the whole reason this sprint is built around the class picker rather than a single difficulty slider.

Class 1 to 5: exactly what NCERT covers, and no further

The bottom five classes are built from docs/ncert-maths-progression.md, a scope document put together by reading the current NCERT primary chapters directly rather than trusting a secondary summary. A few of its findings surprise most parents: there are no decimals anywhere in Class 1 to 5, division never produces a remainder before Class 4, and Class 5 stops at 99,999 with no lakhs or crores at all. This sprint holds every one of those lines. A Class 3 division question here is always exact - never 47 ÷ 5 - because that is what the current Class 3 book actually asks for. A Class 1 subtraction question never produces a negative number, because negative numbers are not primary maths.

The trade-off is the same one our maths worksheet generator is honest about: the current NCERT books are lighter than what many CBSE schools and most parents’ own memory of school still expect. If your child’s school sets 4-digit multiplication in Class 3 and this sprint only offers tables to 100, that is not an error here - it is the current book being lighter than the classroom.

Class 6 to 10: extended sensibly, kept mental-sized

NCERT’s own scope document only covers primary school, so Class 6 upward is our own judgement call rather than a chapter-by-chapter transcription. The rule we held to: whatever appears has to be genuinely doable in your head inside a few seconds. That rules out factorising a quadratic or proving a geometry result - both need paper and working, and typing the final line into a timer does not test the method, only whether the last step is remembered. What stays in are the pieces that really are mental: integers and simple decimals from Class 6, percentages and one-step algebra from Class 7, squares, cubes, roots and linear equations from Class 8, profit and loss and exponent laws from Class 9, and standard trigonometric ratios, arithmetic progressions, simple interest and probability from Class 10.

One deliberate design choice sits underneath Class 7’s integer multiplication and division: those questions are multiple choice, not typed. The reason is a phone, not pedagogy. Most mobiles switch to a number-only keypad the moment a typed answer is a plain integer, and that keypad has no minus key. Where the sign of the answer is the actual point of the question, tapping one of four options is the only fair way to ask it on a touchscreen.

Why a sprint, and why sixty seconds

Fluency is a different skill from understanding. A child can know exactly why 7 × 8 is 56 and still take four seconds to produce it, and that four seconds is expensive the moment it happens inside a long division or a two-step word problem - the working memory spent recalculating a known fact is memory that is not available for the actual question. Sixty seconds of quick, low-stakes recall, done most days, builds that speed far faster than an occasional long session does.

The clock is not the place to start, though. Run the untimed twenty questions first, every time a new class or a new child sits down. A timer measures how fast an answer comes back, and there is nothing to measure until the answer is reliably there at all.