geometry
posted by simthandile .
The square of an integer never hasa last digit equal to:a.1 b.4 c.5 d.8 e.9

a number ending in 0 when squared ends in 0
a number ending in 1 when squared ends in 1
a number ending in 2 when squared ends in 4
a number ending in 3 when squared ends in 9
...
a number ending in 9 when squared ends in 1
investigate. 
http://www.mathwarehouse.com/arithmetic/numbers/listofperfectsquares.php