The sum of the digits of a number formed by any power or index of 9 is always 9.
(v) 9 x 7 = 63 → 6 + 3 = 9
(vi) 9 x 15 = 135 → 1 + 3 + 5 = 9
(vii) 9 x 17 = 153 → 1 + 5 + 3 = 9
(viii) 9 x 19 = 171 → 1 + 7 + 1 = 9
Related Concept
● Patterns and Mental Mathematics
● Counting Numbers in Proper Pattern
● Puzzle
● Patterns
4th Grade Math Activities
From Number Formed by Any Power to HOME PAGE
Didn't find what you were looking for? Or want to know more information about Math Only Math. Use this Google Search to find what you need.

New! Comments
Have your say about what you just read! Leave me a comment in the box below. Ask a Question or Answer a Question.