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 […]

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# Posts by Math Proofs

## The Sum of Two 2-Digit Numbers with Reversed Digits

Let us observe the sum of a 2-digit number and a number formed by reversing its digits. 23 + 32 = 55 63 + 36 = 99 43 + 34 = 77 21 + 12 = 33 26 + 62 = 88. Notice that all the numbers are divisible by 11. Now, are all such […]

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## The Sum of Two Consecutive Odd Numbers

When a is a factor of a number b, then b is divisible by a. For example, 3 is a factor of 12, so 12 is divisible by 3. We will use this concept in the proof in this post. Notice that the sum of the following consecutive odd numbers. 11 + 13 = 24 […]

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