Grade 4 - Progress in Mathematics

Front-End Estimation

3-1

Add the front digits. Write 0s for

the other digits.

Think

7000 
 1000 
 1000  9000

Students in the Hilldale elementary

schools held a Read-a-Thon in

October. About how many books

did they read altogether?

To find about how many,

use front-end estimation:

2534 
 2496 
 3875

2534 2534

2496 2496


 3875 
 3875

7 about 7000 Rough estimate: 7000

To get a closer estimate, make groups

of about 1000 from the other digits.

2534 
 2496 
 3875

about 1000 about 1000 Adjusted estimate: 9000

Altogether, the students read about 9000 books.

Study these examples.

$5.26

1 .52 about $1 738

3 .78 about $1 223 about 100


 2 .45 
 569

about$11. 00 about 1400

$11 
$1 
$1 $13 1400 
 100  1500

Rough estimate: $11 Rough estimate: 1400

Adjusted estimate: $13 Adjusted estimate: 1500

Hilldale Schools

School Books Read

Central 2534

North 2496

South 3875

8204-6_096-097 10/4/07 6:41 AM Page 96