Controller down. Reporter mode on.
Mission:
Rounding Reporters!
The island reporters are live at the festival. To make the numbers easy to remember, they round them. Correctly, of course!
about 12,000 guests!
How to practice: one mission a day (15 to 20 minutes) and 5 minutes in the trainer. Remember: look to the right!
Tablet tip: In the rounding trainer you practice each place, smallest and greatest numbers, and spotting the rounding place, with a hint for every mistake and a 10-problem test.
Open the trainerRounding · tens and hundreds
Rounding Hill
Imagine each number as a ball on a hill. It always rolls to the nearer ten. If it sits right on top, it rolls up.
0, 1, 2, 3, 4 → round down: the digit in the rounding place stays the same. 5, 6, 7, 8, 9 → round up: it goes up by 1. All digits to the right become 0. The sign ≈ means “about”.
Round to the nearest ten
Six numbers.
Round to the nearest hundred
Six numbers.
Rounding big numbers
Breaking News
Reporters round big numbers so people can remember them. But watch out for two traps!
Example, nearest thousand: 247,382, to the right of the 7 is a 3 → 247,382 ≈ 247,000.
9 trap: if the digit in the rounding place is a 9 and you round up, it becomes 0 and you carry 1 to the left, through every 9 in a row: 99,960 ≈ 100,000 (nearest hundred).
Round to the nearest thousand, ten thousand and hundred thousand
| Number | to the nearest thousand | to the nearest ten thousand | to the nearest hundred thousand |
|---|---|---|---|
| 247,382 | |||
| 685,519 | |||
| 349,990 | |||
| 951,500 |
Twelve boxes.
The 9 trap
Four numbers.
The chain trap
Pixel rounds 2,446 to the nearest ten first (2,450) and then to the nearest hundred (2,500).
Two answers.
Rounding ranges
At the Fence
Which numbers end up at the same number when rounded? A deciding digit of 5 is the first one that rounds up.
Smallest and greatest number
A whole number was rounded. What is the smallest and the greatest number it could have been?
Eight numbers.
Which numbers round to 800 (nearest hundred)?
Six numbers.
Digit puzzle
Which digit goes in the box? There is only one possibility.
One digit.
On the number line, mark the smallest and the greatest number that rounds to 270 (nearest ten)
On screen: tap the line to place an arrow, tap again to remove it.
Two arrows.
Rounding in everyday life
The Island News
Newspapers often print rounded numbers. If you look closely, you notice: some numbers are exact, others only about right.
Write the headlines with rounded numbers
Three headlines.
Exact or rounded?
Four sentences.
To which place was 312,468 rounded?
Five numbers.
How exact is the paper?
24,872 spectators watched the island cup in the stadium. The paper says: “About 25,000 fans!”
Two answers.
Everything mixed · like a test
Test Check
Lightning round, true or false and two riddles: show what you can do.
Lightning round
Eight numbers.
True or false?
Five statements.
Riddles
Two riddles.
Traffic light: how sure are you?
Extra · on a tablet or computer
Rounding Trainer
Pick a practice type. If you make a mistake, the trainer shows you which digit decides.
Test: 10 problems
10 problems with a timer. Wrong ones go on your practice list.
Your last tests:
The check buttons count correct boxes. Compare explanations and answer sentences with the answer key yourself.
ANSWER KEY · Try first, then compare.
Answers
1 · Rounding Hill
B 349 ≈ 300 | 351 ≈ 400 | 1,250 ≈ 1,300 | 2,049 ≈ 2,000 | 4,962 ≈ 5,000 | 7,095 ≈ 7,100
Typical mistake: 65 ≈ 60. A 5 always rounds up: 65 ≈ 70.
2 · Breaking News
685,519: 686,000 | 690,000 | 700,000
349,990: 350,000 | 350,000 | 300,000
951,500: 952,000 | 950,000 | 1,000,000
B 2,996 ≈ 3,000 | 39,970 ≈ 40,000 | 99,960 ≈ 100,000 | 19,999 ≈ 20,000
C 1: no | 2: 2,446 ≈ 2,400
Typical mistake: rounding in stages (2,446 → 2,450 → 2,500). Always round straight from the original number.
3 · At the Fence
≈ 2,000 (to the nearest hundred): 1,950 to 2,049
≈ 70,000 (to the nearest thousand): 69,500 to 70,499
≈ 600 (to the nearest hundred): 550 to 649
B 749: no | 750: yes | 801: yes | 849: yes | 850: no | 795: yes
C 5 (3,547 ≈ 3,500)
D arrows at 265 and 274
4 · Island News
B 1: exact | 2: rounded | 3: rounded | 4: exact
C 312,470: ten | 312,500: hundred | 312,000: thousand | 310,000: ten thousand | 300,000: hundred thousand
D 1: thousand | 2: 25,000 − 24,872 = 128
5 · Test Check
B 1: true | 2: false | 3: true | 4: false | 5: false
C 1: 950 | 2: 84
For grown-ups: what helps most
- Always have the child mark the rounding place first, then look at the digit to its right.
- The two most common mistakes: rounding in stages and the 9 trap (e.g. 39,970 to the nearest hundred = 40,000).
- Practice in everyday life: round numbers from the news, sports or games.