This is my fifth blog of tips to do well in math problems. In this blog you will find some tips to do math questions easy. These tricks are easy to remember to do all math calculations:
25. Squaring a two-digit number ending in 5
To find the square of a two-digit number ending in 5, take the first digit, multiply by itself plus one, and then put "25" after it.
Example: To find 652, compute 6 * 7 = 42, and then write "4225" as the answer.
Example: To find 252, compute 2 * 3 = 6, and then write "625" as the answer.
26. Multiplying two numbers when a round number is halfway between them
Suppose you are multiplying two moderately large numbers, 84 and 76. Note that the number 80 is halfway between the two.
This means that 84*76 can be rewritten as
(80 + 4)(80 - 4) which simplifies to two-80 and two - 4, which is easier to figure out: 6400 - 16 = 6384.
27. 20 Multiplications:
24
X48
----
Speed arithmetic people multiply from left to right, too. No matter how you do it, there's plenty to remember here. Let me show you how this is done. It takes practice to get good at it. But, just watch me do this:
2x4 = 8
2x8 = 16
----
96
4x4 = 16
----
112
4x8 = 32
----
1152
See how that is done? The order in which this is done is the trick: left digits, opposite corners, right digits. Bigger numbers can be done in a similar, but more complicated way.
28. Quick Square
Step1: If you need to square a 2 digit number ending in 5, you can do so very easily with this trick.
Step2: Mulitply the first digit by itself + 1, and put 25 on the end.
Step3: That is all
Step4: Ex: 35 ie (3*(3+1)) & 25
Answer: 1225
29 Addition Trick
384 + 467
Once again, to solve this problem, break it down into more manageable parts, and then solve:
384 + (400 + 60 + 7)
= 784 + (60 + 7)
= 844 + 7
= 851
