Rounding
Rounding replaces a more specific, detailed number with an approximate, simpler one — you decide up or down by looking at a single digit.
This is a free explanation of Rounding — a preview, not the full interactive lesson. The lesson, practice, quizzes, and AI Tutor are inside the app.
First find the place you’re rounding to (tens, hundreds, tenths, …), then look at the one digit immediately to its RIGHT. That neighbor decides everything: if it’s 5 or more, round up the digit in the place you’re rounding to; if it’s 4 or less, round down and leave it. Then zero out or drop everything to the right.
For example, rounding 3,742 to the nearest hundred: the hundreds digit is 7, and the digit to its right is 4 — less than 5 — so round down. The 7 stays and the rest become zeros: 3,700.
One case trips people up: rounding up a 9 carries, since 9 + 1 = 10. Rounding 397 to the nearest ten, the 9 rolls over, so 397 → 400. Decimals follow the exact same rule — you just keep fewer places after the point.
Worked example
Round 3,748 to the nearest hundred.
- The hundreds digit is 7.
- Look at the digit to its right (the tens digit): 4.
- 4 is less than 5, so round down — the 7 stays.
- Everything after becomes zero: 3,700.
3,700
On the test: Estimation questions (“about how much…”) are rounding in disguise.
Inside the app, Rounding comes with:
Read the explanation here for free — then practice it for real, with everything you need in one place.
- Practice sets — Open-book practice questions at your level, easiest-first — as many as you want, never scored.
- Quizzes — Scored quizzes on the whole lesson, so you know when you’re ready to move on.
- Skills Check — A concept-by-concept map of what you’ve mastered and what to focus on next.
- Worked examples — Tap the Brain Button on any example for alternative step-by-step explanations.
- Glossary — Plain-English definitions of every key term in the lesson.
- Formula sheet — The GED® & HiSET® formula sheets, on screen while you practice.
- Practice calculator — An on-screen calculator to build your calculator skills before test day.
- Math-fact flashcards — Quick drills for addition, multiplication, perfect squares, and square roots.
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