Vanessa needs 4,490 shells for her project but already has 2,456 shells. To estimate how many more shells she needs, round the numbers to the nearest thousand and subtract. Rounding 4,490 to 4,000 and 2,456 to 2,000, the estimated difference is 2,000 more shells that Vanessa needs.

1. 3

2. Estimating
of
Difference

3. Vanessa collects shells for her
project. She needs 4 490 shells to make
a recycled bag. She already has 2 456.
About how many more shells does
she need?

4. Since the problem asks for
“about how many”,
We just need to estimate the
answer, and not give the actual
value.

5. In other words we need to find
the
“ESTIMATED DIFFERNCE”

6. Vanessa collects shells for her project.
She needs 4 490 shells to make a recycled
bag. She already has 2 456. About how
many more shells does she need?

7. To solve the problem
above, we need to find
the estimated
DIFFERENCE.

8. How to find the
estimated
difference?

9. Step 1:
Round off the
Minuend and subtrahend to
their
greatest place value.

10. Step 2:
Subtract the
rounded-off numbers.

11. Vanessa collects shells for her project.
She needs 4 490 shells to make a recycled
bag. She already has 2 456. About how
many more shells does she need?

12. Vanessa collects shells for her project. She
needs 4 490 shells to make a
recycled bag. She already has 2 456.
About how many baskets of vegetables did he deliver in a week?

13. 4 490
-2 456

14. Step 1:
Round off the
Minuend and subtrahend to their
greatest place value.

15. 4 490
-2 456

16. 4 490
-2 456

17. 4 490
-2 456
4 000
- 2 000

18. Step 2:
Subtract the rounded-off
numbers.

19. 4 490
-2 456
4 000
- 2 000
2 000

20. 4 490
-2 456
2 034
4 000
- 2 000
2 000
actual
difference
estimated
difference
10

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