# Math

posted by .

Is there a trick or formula or easy way to figure out square root mentally?

• Math -

Memorize the common square roots

2 * 2 = 4
3 * 3 = 9
etc.

Then using those squares, you can estimate other square roots.

Example:

square root of 130 =

√ 121 = 11
√ 144 = 12

√ 130 is between 11 and 12

• Math -

Ok. Is there an easy way to figure the perfect square root for numbers 13 through 25.

• Math -

3 * 3 = 9
4 * 4 = 16
5 * 5 = 25

Memorize the squares of 1 - 12

• Math -

So are u saying to memorize the squares for 13 - 25 as well? Not sure if my question is clear. For e.g. square of 23 is 529. By multiplying the last digit of 23 ( 3x3)= 9, same last digit of the number 529, is there a way I easily work out the first 2 numbers 52?

• Math -

ahh, so you want to square the numbers , not take their square roots

A mental way to multiply any two 2-digit numbers
e.g.
34 x 34
4x4 = 16 , so the last digit is 6 , with 1 to carry
3x4+ 4x3 = 24 plus the one to carry is 25
so the tens digit is 5 , with 2 to carry
3x3 = 9 with 2 to carry is 11

so 34^2 = 1156

the numbers don't have to be the same ...

e.g. 56 x 83
6x3 = 18 , so unit digit is 8 , carry 1
5x3 + 6x8 = 63 , so tens digit is 4 , carry 6
5x8 = 40, plus the carry 6 = 46

56x83 = 4648

but really, am I not just doing the steps of ordinary multiplication ??

## Similar Questions

1. ### math

What does it mean to have the sqaure root of 5 with a 2 in front of it?
2. ### Math Help

the square root of 3 times the square root of 15 also the square root of 18 times the square root of 3 To multiply square roots: sq rt of z times the sq rt of y It would be the square root of zy The first one is 3x15 = 45 So it's the …
3. ### Algebra 2

could you walk me thorugh these problems simplfy square root 18 - 3 times sqaure root of 50 plus 5 times the square root of 80 - 2 times the square root of 125 I'm having troubles with the square root of 80 all of the other radicals …
4. ### Algebra

Use the quadratic formula to solve the equation. Give exact answers: 2x^2 -1 = 6x. The choices are: a) -3 + square root(7)/2, -3 - square root(7)/2 b) 3 + square root(11)/2, 3 - square root(11)/2 c) 3 + square root(7)/2, 3 - square …
5. ### square roots

i know this problem is really easy but i am having a brain freeze day will someone please help me figure out what the square root of 32 is?
6. ### Algebra

Rationalize each expression by building perfect nth root factors for each denominator. Assume all variables represent positive quantities. I don’t understand how to compute these. Also I don’t have the square root sign so I typed …
7. ### Math simplifying mixed radicals

Please help me simplify these following mixed radicals:: and show me how you did it cause I need to learn : I don't know how to type a square root sign so I just wrote square root and the numbers infront of the square root are supposed …
8. ### Calculus

A rectangle is bounded by the x axis and the semicircle = square root 25-x^2. What length and width should the rectangle have so that its area is a maximum?
9. ### Math

simplify the expression (4 square root of x)/(6-square root of x) I need help with this. I've worked it out to the point where i got (2 square root of x)/(3-square root of x), but I'm pretty sure that it can be simplified further. …
10. ### Math

simplify the expression (4 square root of x)/(6-square root of x) I need help with this. I've worked it out to the point where i got (2 square root of x)/(3-square root of x), but I'm pretty sure that it can be simplified further. …

More Similar Questions