Rounding and approximating answers
Rounding and approximating answers
There is an emphasis on using large numbers in Years 5 and 6. For example, the new targets for Year 5 Number includes:
• round any number up to 1 000 000 to the nearest 10, 100, 1000, 10 000 and 100 000
Now this might sound fairly straightforward but for many children it will pose considerable difficulty. By Year 5 children should already be able to round to the nearest 10, 100 and probably 1 000, but dealing with very large numbers can cause confusion.
When rounding to the nearest 10 000 the key figure is the thousands digit. If the thousands digit is 5 or above, round up. If it is below 5, round down.
e.g. 327 550 is 330 000 to the nearest 10 000.
324 259 is 320 000 to the nearest 10 000
(Note that WHEN ROUNDING TO 10 000 it does not matter what the hundreds, tens or units digits are, it is the THOUSANDS digit which must be looked at.)
When rounding to the nearest 100 000 the key figure is the ten thousands digit. If the ten thousands digit is 5 or above, round up. If it is below 5, round down.
e.g. 277 550 is 300 000 to the nearest 100 000.
237 259 is 200 000 to the nearest 100 000
Be careful that when rounding, children do not write:
2 345 = 2 000
because 2 345 does not equal 2 000.
Why not take a look at our most recent rounding worksheets for Year 5?