In the previous post, we proved a theorem that the sum of a 2-digit number with reversed digit is divisible by 11. In this post, we will learn another theorem about numbers with reversed digits. This time, we will explore the difference between two 3-digit numbers with reversed digits. Let’s have the following examples. 231 […]

Continue reading…

# Grades 9-12

## The Sum and Product of Roots Theorem

From the quadratic formula, we know that the numbers and are the roots of the quadratic equation where if and only if and .

Continue reading…

## Sample Proof on Triangle Congruence Part 3

Recall that for real numbers a, b, and c are real numbers, if and , then . This is called Transitive Property of Equality. This is also the same with congruence. If , , and are polygons, and if is congruent to , and is congruent , then is congruent to . This is called […]

Continue reading…