Question

Find the value of each of the following using the short-cut or column method: $(25{)}^3$

Answer 1

${25}^3={(20+5)}^3$
It is the form of ${(a+b)}^3$, where $a=20,b=5$
Applying the formula ${(a+b)}^3=a^3+b^3+3ab(a+b)$
${25}^3={(20+5)}^3={20}^3+5^3+3\times 20\times 5\times (20+5)=8000+125+7500=15625$