ACT Preparation / Unit 19 ACT 1818 short lesson, about 20 seconds
Estimating Without a Calculator
Captions available
The idea
Science questions need only simple arithmetic: differences, ratios and rough percents. Rounding to friendly numbers first is often enough to choose between answers.
In practice
47 out of 198 is close to 50 out of 200, about 25%.
Where people slip
Estimate only as finely as the choices require; if they are far apart, a rough figure decides.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
Unlocks
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