Grades 9-10 Video Solutions 2010-Levels 9&10 Video Solutions 2010 problem6

Levels 9&10 Video Solutions 2010 problem6

Video Transcription

Video Summary

The video explains how to find the sum of a series of odd numbers, specifically from 1 to 77. It illustrates the relationship between the number of odd numbers and a perfect square using a grid representation. For example, the sum 1 + 3 + 5 + 7 equals 4². The general pattern involves counting the odd numbers, adding 1 to the last odd number, dividing by 2, and squaring the result. For the sum up to 77, there are 39 odd numbers, so the result is 39² or 1521, leading to answer B.

Keywords

sum of odd numbers

perfect square

grid representation

mathematical pattern

series calculation