1) Multiplication of two digit number by 11
Lets take the case 23X11
Step1) Split the number 23 like this,2——-3
Step2) Add the digits of the two digit number . 2+3=5
step3) Place this in the blank space in step 1
So Solution 253
Lets take the case of 57X11
Step1) Split the number 57 like this,5——-7
step2) Add the digits of the two digit number . 5+7=12
Step 3) In such just place the second digit of the number in the blank space and carry over the first digit over the first digit of the original
So solution 627
2) Squaring any two digit number ending with digit 5
Lets take the example of 65
step 1) Multiply the tens place number by the next number ie, 6X7=42
step 2) The square of 5 is 25
Solution is 4225
3) Square any two digit number starting with 5
Lets take the example of 58
step1) Square the fisrt digit and add the second digit to it.
So 25+8=33
Step 2) Square the second digit i.e 8X8=64
Step 3) combine them
3364
4) Fraction,decimal and percentage to remember
Fractions | Decimals | Percents |
1/2 | .5 | 50% |
1/3 | .3 | 33.3% |
2/3 | .6 | 66.6% |
1/4 | .25 | 25% |
3/4 | .75 | 75% |
1/5 | .2 | 20% |
2/5 | .4 | 40% |
3/5 | .6 | 60% |
4/5 | .8 | 80% |
1/6 | .16 | 16.6% |
5/6 | .83 | 83.3% |
1/8 | .125 | 12.5% |
3/8 | .375 | 37.5% |
5/8 | .675 | 62.5% |
7/8 | .875 | 87.5% |
1/9 | .1 | 11.1% |
1/10 | .1 | 10% |
1/11 | .09 | 9.09% |
1/12 | .083 | 8.3% |
1/16 | .0625 | 6.25% |
1/20 | .05 | 5% |
1/25 | .04 | 4% |
1/50 | .02 | 2% |