Lakshadweep TET – Quantitative Aptitude
Topic: Tables
Tables are pre‑calculated lists of numbers that help you solve arithmetic problems quickly without having to perform long calculations.
In TET exams you’ll see questions that explicitly ask you to use tables or that can be solved efficiently by referring to a table.
1. What are Tables?
| Table | Purpose | Typical Numbers Covered |
|---|---|---|
| Multiplication Table | Find the product of two numbers (usually 1–10) instantly | 1 to 10 (and sometimes 1 to 12) |
| Times Table | Same as multiplication table but often listed per factor (e.g., 2‑table, 3‑table, …, 10‑table) | 2,3,4,5,6,7,8,9,10 |
| Addition Table | Quickly add two numbers (mostly useful for mental math) | 1–12 |
| Frequency Table | Summarise data in statistics (not usually a TET question, but good to know) | Any set of data |
| Division Table | Find quotients and remainders without long division | 1–10, sometimes 1–12 |
Quick tip: Memorise the 2–10 tables (2‑table to 10‑table). They are the backbone of most arithmetic problems in the exam.
2. Types of Tables & How to Use Them
| Type | How to Use | Sample Entry |
|---|---|---|
| Multiplication / Times Table | Look up the row or column that matches one of the factors. | 7 × 8 = 56 (from 7‑table or 8‑table) |
| Addition Table | Add the two numbers by checking the corresponding row/column. | 9 + 6 = 15 |
| Division Table | Use the table to get quotient and remainder. | 32 ÷ 4 = 8 (no remainder) |
| Frequency Table | Count occurrences of each value in a data set. | Number of students scoring 80–85%: 12 |
Remember:
- For multiplication of numbers >10, decompose: e.g.,
12 × 13 = (10+2) × (10+3) = 100 + 30 + 20 + 6 = 156.- Use the 10‑table to handle the “10s” part quickly.
3. Key Points & Tips
- Memorise 2–10 tables – These are the most frequent in TET papers.
- Use the “10‑table” for any number with a unit digit
Example:34 × 7 = (30 + 4) × 7 = 210 + 28 = 238.
Check 7‑table for 30 (i.e.,7 × 3 = 21→210) and 7‑table for 4 (28). - Cross‑check using both factors – If you’re unsure, look at both the row of the first factor and the column of the second.
- Practice “back‑calculation” – If you know the answer, check how it would appear in the table to avoid mistakes.
- Speed drills – Write a quick 2–10 table on a sheet and practice multiplying random pairs from it.
4. Worked Example
Question (TET‑style):
A teacher wants to calculate the total marks obtained by 12 students in a test. The marks of each student are:
78, 85, 92, 68, 73, 88, 77, 91, 84, 69, 80, 86.
Use a frequency table to find the total and the average.
Step‑by‑Step
| Score | Frequency |
|---|---|
| 68 | 1 |
| 69 | 1 |
| 73 | 1 |
| 77 | 1 |
| 78 | 1 |
| 80 | 1 |
| 84 | 1 |
| 85 | 1 |
| 86 | 1 |
| 88 | 1 |
| 91 | 1 |
| 92 | 1 |
Why a frequency table?
It lets us see how many times each score appears (all once in this case), making it easy to compute the sum.
Sum:
68 + 69 + 73 + 77 + 78 + 80 + 84 + 85 + 86 + 88 + 91 + 92
= 938
Average: