speed math

Multiplication of polynomials using duplex method 

Simultaneous equation using cross multiplication technique

Use cross multiplication to solve the equation:

5x- 3y -1=0 -------------- (1)
x +2y- 12=0 --------- (2)

Multiplication of numbers closer to 100 (part 2)

Multiplication of numbers closer to 100  (> 100)

Multiplication of numbers closer to 100

Multiplication of  numbers closer to 100 (< 100)

Say, the numbers are 93 x 97

step 1. find out how far the numbers are  from 100.

so,         93 --------7
              97--------3

step 2. multiply  7 x 3 and record as 21.

step 3. subtract 3 from 93 or 7 from 97, both will always be same.
so, we have 93 - 3 = 90, or 97 - 7 = 90
step 4. write the answer as 9021

Let me take some more examples;

say I want to multiply 89 x 94

so,         89 --------11
              94--------6
             83    /      66 --------8366 is the answer

step 2. multiply  11 x 6 and record as 66.

step 3. subtract 11 from 94 or 6 from 89, both will always be same.
so, we have 94 - 11 = 83, or 89 - 6 = 83
step 4. write the answer as 8366.

with a little practice you can write the answer immediately.


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equation - practice problem STD IV

solving equations 1

square of number between 50 and 60

SQUARE OF NUMBERS BETWEEN 50 TO 60

Let's take the number 51

• first square the number 1. if the outcome is single digit number then record as 01.
• Now add 25 to the number 1. ie. (25 + 1) =26
• result = 2601

Now, let us take another number 52

• square of 2 is 4. Since it is a single digit number, record as 04.
• Add 25 + 2 = 27
• result = 2704

Now, let us take another number 54

• square of 4 is 16. record it as 16.
• Add 25 + 4 = 29
• result = 2916

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SQUARE OF NUMBERS ENDING WITH 5

TECHNIQUE

let's take a number 45

• first write 25.
• then multiply the number 4 with the immediate next number, i.e. 5, so, 4 x 5 = 20
• therefore the answer is 2025

Now let's take the number 85.

• the answer would be (8x9)25 =7225

Similarly we can find the square of the number 65

• the answer would be (6x7)25 =4225

Similarly we can find the square of the number 115

• the answer would be (11x12)25 =1322                                                                                     those who read this also read 

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