The brutal truth about 90 days
Imagine two students, both studying five hours a week. Student A tries to 'cover everything' and touches fourteen topics once. Student B picks five, goes deep, and revisits them every week. In January, Student B almost always looks calmer — because the same ideas keep showing up in different costumes, and Student B has met each costume before.
That is the principle behind this priority map: depth on a short list beats breadth on a long one. The AMC 8 draws on content most Indian middle-schoolers have seen. What changes is how it is asked.
The priority map
| Tier | Topics | How often | Why |
|---|---|---|---|
| 1 - Drill | Counting and probability; number theory (divisibility, primes, LCM/HCF, units digits); ratios, percentages, rates | 3-4 times a week | High reward for practice; very learnable patterns |
| 2 - Revise | Geometry: area, perimeter, Pythagoras, angle chasing, similar triangles | 2 times a week | Diagram skill takes repetition, not new theory |
| 3 - Maintain | Algebra word problems, equations, patterns and sequences, averages | Weekly | Usually familiar from school; keep it warm |
| 4 - Park | Anything beyond Grade 8 syllabus (trigonometry, logarithms, heavy coordinate geometry) | Skip | Not needed; costs time you do not have |
Tier 1 in action: three problems worth your time
Counting: digit sums
How many three-digit numbers have digits that add up to 4? Fix the hundreds digit and count the ways the other two digits can finish the sum. With hundreds digit 1, the other two digits sum to 3: (0,3), (1,2), (2,1), (3,0) is 4 ways. With 2, they sum to 2: 3 ways. With 3, they sum to 1: 2 ways. With 4, they sum to 0: 1 way. Total: 4 + 3 + 2 + 1 = 10. The lesson is the habit — organise a count by fixing one variable — which solves a huge family of problems.
Number theory: the units-digit cycle
What is the units digit of 7 to the power 2027? Powers of 7 end in 7, 9, 3, 1, then repeat every four steps. Divide 2027 by 4: the remainder is 3, so we land on the third entry of the cycle, which is 3. Notice that nothing here needs a calculator — only a pattern and a remainder.
Ratio and percent: work in a convenient number
A price rises by 20% and then falls by 20%. What is the net change? Many students answer 'no change'. Start with 100: after the rise it is 120, and 20% of 120 is 24, so it falls to 96. The net change is a 4% decrease. Choosing 100 (or 10, or 60) as a starting number turns abstract percent traps into plain arithmetic.
Got a question about this?
Talk to an AMC 8 & 10 Coaching mentor directly — no form, just a quick WhatsApp chat.
Tier 2: one geometry trick that repays you
A right triangle has legs 6 and 8, so its hypotenuse is 10. What is the altitude to the hypotenuse? Find the area two ways. Using the legs: (6 x 8) / 2 = 24. Using the hypotenuse as base with altitude h: (10 x h) / 2 = 24, so h = 4.8. 'Compute the same area two ways' is one of the most useful ideas in middle-school geometry, and it appears again and again.
What to do with your weekly 5 hours
- About 2.5 hours on Tier 1 problems from a mix of sources.
- About 1 hour on Tier 2, with a fresh diagram drawn for every problem.
- About 45 minutes on Tier 3 and the daily mental-arithmetic warm-up.
- About 45 minutes reviewing the error log — the highest-return slot of the week.
Three traps in the last 90 days
- Resource hopping. Pick two good sources and finish them. See our book and resource guide.
- Chasing hard problems. The AMC 8 rewards getting the first 15 right and quick, not proving you can solve a puzzle meant for higher levels.
- Skipping the slow review. Doing 40 problems and reviewing none teaches less than doing 15 and reviewing all.
For a closer look at what the paper actually contains, read AMC 8: Most Likely Question Types, and avoid the common AMC 8 mistakes as you go.
