Reading, Writing and Comparing Whole Numbers Beyond 1,000,000
Primary 6 · Mathematics
Reading, Writing and Comparing Whole Numbers Beyond 1,000,000
Lesson 6 of 6
30 min
Let's begin
A newspaper says, “About 13 million people live in Rwanda.” But the census counted 13 246 394. Is the newspaper wrong? No! It rounded the number, so it is easier to remember and to say.
13 246 394 lies between 13 000 000 and 14 000 000. The halfway point is 13 500 000. Our number is below halfway, so it is closer to 13 000 000. Rounded to the nearest million, it is 13 000 000.
Worked example
Round 4 386 257 to different places.
| Round to the nearest … | Digit to look at | Up or down? | Answer |
|---|---|---|---|
| ten | 7 (ones) | up | 4 386 260 |
| hundred | 5 (tens) | up | 4 386 300 |
| thousand | 2 (hundreds) | down | 4 386 000 |
| ten thousand | 6 (thousands) | up | 4 390 000 |
| hundred thousand | 8 (ten thousands) | up | 4 400 000 |
| million | 3 (hundred thousands) | down | 4 000 000 |
Worked example
Round 2 997 800 to the nearest ten thousand.
Rounding helps you check big calculations. Worked example: Estimate 2 485 000 + 3 512 000 by rounding to the nearest million: 2 000 000 + 4 000 000 = 6 000 000. The exact answer is 5 997 000, which is very close.
Do not round in steps. To round 4 449 999 to the nearest million, look only at the hundred thousands digit (4): the answer is 4 000 000. If you round to 4 450 000 first, then 4 500 000, then 5 000 000, you get the wrong answer.
Tip
“5 or more, raise the score. 4 or less, let it rest.” Look only at the ONE digit to the right of your rounding place.
Work each one in your exercise book first, then tap Show answer to check.
Round 6 752 481 to the nearest thousand.
Answer: 6 752 000. The hundreds digit is 4, so round down.
Round 6 752 481 to the nearest hundred thousand.
Answer: 6 800 000. The ten thousands digit is 5, so round up.
Round 19 960 000 to the nearest hundred thousand.
Answer: 20 000 000. 9 rounds up to 10, so carry into the millions.
Estimate 7 815 000 − 3 290 000 by rounding each number to the nearest million.
Answer: 8 000 000 − 3 000 000 = 5 000 000. (The exact answer is 4 525 000.)
What you learned today
Sources and credits
The stories, Rwandan worked examples and practice questions were written by Ganzaa.
Quick check
Round 8 463 527 to the nearest hundred thousand.
