Its always better to be thorough with the following. This will help u in doing quick calculations. If u are proficient in this, then u can do speed calculations.
Multiplication tables - (1*15) up to (20*15)
Squares up to 25
Cubes upto 12
Powers of 2 - up to 12
Powers of 3 - upto 6
Reciprocals of numbers - upto 12
Compliments of 100 (i.e. the differance between 100 and the given two-digit number. eg- 25's compliment is 100-25 = 75)
.4\(^5\) = ?
2\(^10\) = 4\(^5\) = 1024.
.4 has one decimal place. so when its multiplied 5 times, u need to put 5 decimal places to the left of 1024.
so answer is 0.01024
same way do .25\(^4\)
25*25 = 625
625*2 = 25\(^4\) = 390625
now count the decimal points. Ans=0.390625
U are supposed to know the techniques for speed mathematics.
Once u master those techniques, then u can do a lot of lengthy calculations like multiplication of a 3 digit number with another 3 digit number, squaring a three digit number and the like in few seconds.
Shall start a new post on speed mathematics soon. if there is already a thread on that, then somebody plz attach the link here
If u think this post is useful plz feed me with a kudo