Division is where time goes. Divide by 5, 25 and 125 by multiplying instead, compare fractions without dividing, and approximate when the options are far apart.
Most students lose time dividing. Dividing by 25 is harder than multiplying by 4, so do the multiplication instead.
Simplification and approximation questions ('approximately what value should replace ?') appear in most placement tests and bank-style papers. They reward three habits: turning division into multiplication, comparing fractions without long division, and rounding when the options allow it.
5 = 10/2, so dividing by 5 is the same as multiplying by 2 and dividing by 10. 25 = 100/4 and 125 = 1000/8 work the same way.
Dividing by 10, 100 or 1000 only moves the decimal point, so all the real work is a doubling or a × 4 or a × 8.
4,375 / 125
Answer: 35
To compare a/b with c/d, cross-multiply: compare a × d with b × c. Whichever side has the bigger product has the bigger fraction.
For several fractions, convert to percentages with the fraction table, or compare how far each is from 1 (1 - a/b).
Which is bigger: 13/17 or 16/21?
Answer: 13/17
Order: Brackets, then 'of', then Division and Multiplication from left to right, then Addition and Subtraction from left to right.
Division does NOT come before multiplication. They share one level and you go left to right. 12 / 3 × 2 = 4 × 2 = 8, not 12 / 6 = 2.
Simplify 48 / 4 × 3 + 5 - 2 × 6
Answer: 29
If the answer options are more than about 10% apart, you do not need the exact value. Round every number to the nearest friendly value, compute, and pick the nearest option.
Round in opposite directions when you can (one up, one down) so the errors cancel.
Approximately: 399.8 × 24.9 / 50.1 = ? (a) 150 (b) 200 (c) 250 (d) 300
Answer: 200
Give each question at most 90 seconds on the first pass. If you are not near the answer by then, mark it and move on.
Look at the options before calculating: the unit digit, the size or the form of the answer often rules out two of them.
Do the easy topics of your paper first (percentages, averages, series), then return to the long ones (DI, puzzles).
| Situation | What to do |
|---|---|
| Options far apart | Approximate |
| Options close together | Compute exactly, check the unit digit |
| 'Find the number' type | Try the options from the middle |
| No starting value given | Take 100 or the LCM |
| Stuck after 90 s | Mark, skip, come back |
Arrange 3/5, 5/8, 4/7 in increasing order.
Answer: 4/7, 3/5, 5/8
Simplify: 18 + 6 / 3 × 2 - 4
Answer: 18
Approximately what is 49.98% of 801.2 + 24.9% of 399.7? (a) 480 (b) 500 (c) 520 (d) 560
Answer: 500
What is 3/7 as a decimal, to 6 places?
Answer: 0.428571
9 questions with full solutions.