227
- = x 0 1 2 3 4 5 6 7 8 9 ( ) % < > + - = x 0 1 2 3 4 5 6 7 8 9 ( )
% < > + - = x 0 1 2 3 4 5 6 7 8 9 ( ) % < > + - = x 0 1 2 3 4 5 6 7 8 9
( ) % < > + - = x 0 1 2 3 4 5 6 7 8 9 ( ) % < > + - = x 0 1 2 3 4 5 6 7 8
9 ( ) % < > + - = x 0 1 2 3 4 5 6 7 8 9 ( ) % < > + - = x 0 1 2 3 4 5 6 7
8 9 ( ) % < > + - = x 0 1 2 3 4 5 6 7 8 9 ( ) % < > + - = x 0 1 2 3 4 5 6
7 8 9 ( ) % < > + - = x 0 1 2 3 4 5 6 7 8 9 ( ) % < > + - = x 0 1 2 3 4 5
6 7 8 9 ( ) % < > + - = x 0 1 2 3 4 5 6 7 8 9 ( ) % < > + - = x 0 1 2 3
S SQUARING NUMBERS QUARING NUMBERS
EENDING IN 5NDING IN 5
When you multiply a number by itself (for example, 3 × 3, or 5 × 5,
or 17 × 17), you are squaring it. Seventeen squared (or 17 × 17) is
written as: 17^2. Th e small 2 written after the 17 tells you how many
seventeens you are multiplying. If you wrote 17^3 it would mean
three seventeens multiplied together, or 17 × 17 × 17.
Now, to square any number ending in 5, you simply ignore the 5 on
the end and take the number written in front. So, if we square 75
(75 × 75), we ignore the 5 and take the number in front, which is 7.
Add 1 to the 7 to get 8. Now multiply 7 and 8 together.
7 × 8 = 56
Th at is the fi rst part of the answer.
For the last part you just square 5.
5 × 5 = 25
Th e 25 is always the last part of the answer. Th e answer is 5,625.
AAppendix Jppendix J
bbapp10.indd 227app 10 .indd 227 1 1/5/07 11:38:59 AM/ 5 / 07 11 : 38 : 59 AM
- = x 0 1 2 3 4 5 6 7 8 9 ( ) % < > + - = x 0 1 2 3 4 5 6 7 8 9 ( )