128 страниц. 2010 год. LAP Lambert Academic Publishing This study explored the relationship between estimation skill and computational ability for whole and rational numbers. The methods carried out were both quantitative as well as qualitative and data were collected from three primary schools along with their associated high schools. The year levels chosen were 5, 7 and 9. The results of the study shows that performance in estimation is positively correlated with written computation in all the year levels. Hence, the findings indicate that a child who is good in estimation skill can also perform well in written computation. As such, the importance of achieving estimation skill in a child would be very helpful in solving computation problems with understanding.