Easily square numbers from 401 to 499.
Example
{% scaleimage l309_example.png %}
Step 1
Square the last 2 digits.
{% scaleimage l309_step1.png %}
Step 2
Multiply the last two digits by 8.
05 x 8 = 40
Step 3
Add two zeros to the end of step 2.
40 x 100 = 4000
Step 4
Add the results of step 1 and step 3.
4000 + 25 = 4025
Step 5
Add 160000 to the result of step 4.
160000 + 4025 = 164025
{% scaleimage lesson_underline.png %}