Easily square numbers from 201 to 299.
Example
{% scaleimage l307_example.png %}
Step 1
Square the last 2 digits.
{% scaleimage l307_step1.png %}
Step 2
Multiply the last two digits by 4.
05 x 4 = 20
Step 3
Add two zeros to the end of step 2.
20 x 100 = 2000
Step 4
Add the results of step 1 and step 3.
25 + 2000 = 2025
Step 5
Add 40000 to the result of step 4.
40000 + 2025 = 42025
{% scaleimage lesson_underline.png %}