Quick Start Guide

Speed Maths Square Calculator calculates square of a number using different speed maths methods. The methods are selected according to the number entered, to perform the calculations faster. It displays all the steps used for the calculations.

The methods used by this calculator are provided below.

Let's calculate $381^2$ using this method.

Step 1: Write the first row

The first row is obtained in the following pattern.

For a two digit number ab, first row is
D(a) | D(ab) | D(b)

For a three digit number abc, first row is
D(a) | D(ab) | D(abc)| D(bc)| D(c)

For a four digit number abcd, first row is
D(a) | D(ab) | D(abc)| D(abcd)| D(bcd)| D(cd)| D(d)

so on.

Note that D($3$) represents Duplex of $3,~$ D($38$) represents Duplex of $38$ and so on.

Step 2: Calculate Duplex

For a single digit number,
D(a)= a²

For a two digit number,
D(ab)= 2 × a × b

For a three digit number,
D(abc)= 2 × a × c + b²

For a four digit number,
D(abcd)= 2 × a × d + 2 × b × c

For a five digit number,
D(abcde)= 2 × a × e + 2 × b × d + c²

Thus, for our example
D($3$) $=3^2=9$
D($38$) $=2×3×8=48$
D($381$) $=2×3×1+8^2=70$
D($81$) $=2×8×1=16$
D($1$) $=1^2=1$

Step 3: Adjust Carries as applicable.

Take our example. From $16,$ take $1$ as carry which is added to $70$ making it $71$

Repeat this process from right to left. So, from $71$, take $7$ as carry which is added to $48$ making it $55$

From $55$, take $5$ as carry which is added to $9$ making it $14$

Calculate squares of different numbers using this calculator and get familiar with these speed maths methods for squares. Once we have a fair understanding of these, squares can be calculated faster, which is obviously an advantage in competitive examinations.