Arithmetic
About 6 min · Mathematics · English
Time worked out from the lesson's 311 words at 150 words a minute, plus a minute for each question.
Arithmetic is part of the Mathematics section in AP TET Paper I and Paper II. This topic tests your ability to handle everyday numerical problems involving percentages, ratios, profit-loss calculations, and interest computations—skills essential for teaching mathematics at the primary and upper primary levels.
Key ideas
- Percentage means "per hundred": x% = x/100. Converting between percentages, fractions, and decimals is foundational (e.g., 25% = 1/4 = 0.25).
- Ratio expresses a relationship between two quantities in the same unit. Written as a:b or a/b. Ratios have no units; they compare magnitudes.
- Proportion states that two ratios are equal: If a:b = c:d, then a×d = b×c (cross-multiplication rule).
- Cost Price (CP) is what you pay; Selling Price (SP) is what you receive. Profit or loss is always calculated on CP unless stated otherwise.
- Simple Interest (SI) is calculated on the original principal only: SI = (P × R × T)/100.
Quick reference
- x% of N = (x × N)/100 — always divide by 100.
- Successive % change (a%, then b%): Net = a + b + (ab/100).
- Profit % = (Profit/CP) × 100 — never on SP.
- SI = PTR/100 — linear growth; CI uses (1 + R/100)^T — exponential growth.
- Ratio a:b → parts are a/(a+b) and b/(a+b) of the total.
Check yourself: 3 questions
1. A shopkeeper marks an article 20% above its cost price and then allows a discount of 10%. If he still makes a profit of Rs. 80 on the article, what is the cost price of the article?
2. The ratio of boys to girls in a class is 3:2. If there are 15 boys in the class, how many total students are there?
3. A sum of Rs. 8000 is invested at 10% simple interest per annum. What will be the total amount after 3 years?
This lesson is cut from the topic's note, not rewritten. Fact-checked on 18 Oct 2026: an AI-assisted check of this note against cited sources; the errors it found were corrected that day. Some errors may remain. The questions are from Shishya's validated question bank.
Read the full noteFlashcards for this topic
Saves this lesson and its 3 questions in this browser on this phone. No sign-in; nothing about you is saved or sent. A saved copy is not updated until you save it again. Parts that load from the server when you use them (the AI tutor, adaptive practice, sign-in) still need a connection.