Attention Math

NCERT · Class 10 Mathematics

Attention Math

Learning where to look.

Many mistakes in maths happen before any calculation, when your eyes land on the wrong part of the problem. Attention Math teaches the habit of looking in the right place, in two ways.

ConceptsOne place to look in eachEvery concept in the book, with the place to look first and the tempting place not to.Start with Chapter 1Problem solvingThe clue is in the questionReal problems where one detail makes the long route unnecessary. Find the clue, see both routes.How problem solving works

14 chapters · 56 concepts · 26 problems · 9 lenses

What attention means

Look at (n − 1): it counts jumps, not terms.

aₙ = a + (n − 1)d

Look hereNot here
Look here
The jump count, n − 1. It counts the jumps from the first term. The first term is zero jumps away, so the nth term is n − 1 jumps away.
Not here
The position, n. The position n is one more than the number of jumps. Using n gives a + nd, one step too far.
What it teaches
Count the moves, not the stops. Off-by-one mistakes come from counting the wrong thing.
See it in concept 5.3: The nth Term

Inside a concept

Every concept works the same way

All 56 concepts are built from the same five parts, so once you know one page you know them all. This is concept 10.4, from Circles.

A concept page: the formal statement, the intuition and the attention section on the left, the diagram card and Check understanding button on the right.
  1. 1

    Formal statement

    The NCERT definition, word for word. Nothing is skipped or simplified.

  2. 2

    The intuition

    Why it is true, in plain words, on ruled paper.

  3. 3

    The attention

    The new layer: where to look, where not to look, and the habit it teaches.

  4. 4

    What it looks like

    A diagram drawn from the lesson's own numbers, never a stock picture.

  5. 5

    Check understanding

    Tap where you'd look, get a hint or a trap warning, then try a fresh example. At the end you see where your attention went.

Open this concept

Problem solving

The clue is in the question

Every problem has a clue. The clue tells you which lens to use, and the lens makes the problem short. Each problem page asks where you would look first, then shows the route with the lens beside the textbook route.

Three words do all the work: the clue, the lens and the trap. The 9 lenses recur across the whole book, each named by what you look at.

How problem solving worksTry this problem

26 problems so far

One problem, marked up

The altitude of a right triangle is 17 cm less than its base. If the hypotenuse is 25 cm, find the perimeter of the triangle.

The clueThe trap
The lens
The known fact. Look for a fact you already hold: a Pythagorean triple, a special angle, a pair of conjugate roots, a perfect square.

The book

Every chapter of Class 10

In the order of the NCERT book. Each card shows a picture from the chapter's first concept.