| Sunday, May 20, 2007 |
| Squaring numbers in the 700s |
1. Choose a number in the 700s (practice with smaller numbers, then progress to larger ones).
2. Square the last two digits (keep the carry): _ _ _ _ X X
3. Multiply the last two digits by 14 andadd the carry: _ _ X X _ _
4. The first two digits will be 49 plus the carry: X X _ _ _ _
Example:
1. If the number to be squared is 704:
2. Square the last two digits (keep the carry): 4 × 4 = 16: _ _ _ _ 1 6
3. Multiply the last two digits by 14 andadd the carry: 14 × 4 = 56: _ _ 5 6 _ _
4. The first two digits will be 49 plus the carry: 4 9 _ _ _ _
5. So 704 × 704 = 495,616.
See the pattern?
1. If the number to be squared is 725:
2. Square the last two digits (keep the carry): 25 × 25 = 625: _ _ _ _ 2 5
3. Multiply the last two digits by 14 andadd the carry: 14 × 25 = 10 × 25 + 4 × 25= 250 + 100 = 350. 350 + 6 = 356: 56: _ _ 5 6 _ _
4. The first two digits will be 49 plus the carry: 49 + 3 = 52: 5 2 _ _ _ _
5. So 725 × 725 = 525,625. |
posted by marhadi @ 7:07 AM  |
|
|
|
|
| Squaring numbers in the 600s |
1. Choose a number in the 600s (practice with smaller numbers, then progress to larger ones).
2. The first two digits of the square are 36: 3 6 _ _ _ _
3. The next two digits will be 12 times the last 2 digits: _ _ X X _ _
4. The last two places will be the square of the last two digits: _ _ _ _ X X
Example:
1. If the number to be squared is 607:
2. The first two digits are 36: 3 6 _ _ _ _
3. The next two digits are 12 times the last 2 digits: 12 × 07 = 84: _ _ 8 4 _ _
4. Square the last 2 digits: 7 × 7 = 49: _ _ _ _ 4 9
5. So 607 × 607 = 368,449.
For larger numbers reverse the steps:
1. If the number to be squared is 625:
2. Square the last two digits (keep carry): 25x25 = 625 (keep 6): _ _ _ _ 2 5
3. 12 times the last 2 digits + carry: 12x25 = 250 + 50 = 300 + 6 = 306: _ _ 0 6 _ _
4. 36 + carry: 36 + 3 = 39: 3 9 _ _ _ _
5. So 625 × 625 = 390,625. |
| posted by marhadi @ 7:04 AM |
|
|
|
|
| Squaring numbers in the 500s |
1. Choose a number in the 500s (start with low numbers at first; then graduate to larger ones).
2. The first two digits of the square are 25: 2 5 _ _ _ _
3. The next two digits will be 10 times the last 2 digits: _ _ X X _ _
4. The last two places will be the square of the last two digits: _ _ _ _ X X
Example:
1. If the number to be squared is 508:
2. The first two digits are 25: 2 5 _ _ _ _
3. The next two digits are 10 times the last 2 digits: 10 × 8 = 80: _ _ 8 0 _ _
4. Square the last digit: 8 × 8 = 64: _ _ _ 6 4
5. So 508 × 508 = 258,064.
For larger numbers reverse the steps:
1. Square the last two digits (keep the carry): _ _ _ _ X X
2. 10 times the last two digits + carry: _ _ X X _ _
3. 25 + carry: X X _ _ _ _
See the pattern?
1. If the number to be squared is 525:
2. Square the last two digits (keep the carry): 25 × 25 = 625 (keep 6): _ _ _ _ 2 5
3. 10 times the last two digits + carry: 10 × 25 = 250; 250 + 6 = 256 (keep 2): _ _ 5 6 _ _
4. 25 + carry: 25 + 2 - 27: 2 7 _ _ _ _
5. So 425 × 425 = 275,625. |
| posted by marhadi @ 7:02 AM |
|
|
|
|
| About Me |
|
![]()
Name: marhadi
Home: Bekasi, Jawa Barat, Indonesia
About Me:
See my complete profile
|
| Previous Post |
|
| Archives |
|
|
| Artikel |
jika kamu memiliki blog atau website dapatkan ribuan dollar perbulan dari internet dengan bergabung di google adsense, semuanya gratis
|
| Links |
|
|
| Powered by |
|
|