Question

Without actual calculations, find the value of the following expression:
${28}^2-{27}^2$.

Answer 1

Given, ${28}^2-{27}^2$.

We know, $(a+b)(a-b)=a^2-b^2$.

Then,

${28}^2-{27}^2=(28-27)(28+27)=1\times 55=55$.

Hence, $55$ is the required answer.