Topics · Fractions & Decimals
Decimals and rounding
Decimals live on the same number line as fractions. Rounding picks the closer neighbour: 4.36 is about 4.4.
Rounding helps you guess a price, a distance or a time — fast.
More ways into this idea
Step into a storyThe Photo FinishTwo runners, two clocks, and a difference thinner than a blink.- Make it a gameAbout How Much?Throw a net over the number line before you calculate
- Make it a gameNumber LandingGuide each decimal to its closest landing pad
- Test yourselfA fresh mixed set, whenever you likeExplanations after every question. Nothing is recorded.
Common sticking points
- A common sticking point is 'rounding always goes up'. Rounding is a race: the CLOSER neighbour wins, and sometimes that's down.
- Another is thinking a longer decimal is bigger (0.35 vs 0.8). Thinking in hundredths fixes it: 80 beats 35.
Try this together
On a walk or drive, spot a number with a decimal (a price, a distance). Ask: what is it close to? Is $4.29 closer to $4 or $5? How do you know?
1–5 minutes, no materials to buy, nothing to hand in.
Ontario curriculum details
- B1.5Read, show and compare decimals to hundredths
- B1.6Round decimals to the nearest tenth
Plain-language summaries. See the full curriculum for every expectation and the official source.