Squares of 110 to 116 –
Well, I am not going to start it from 101 but from 110 because normally the interest rates are given in
the question from 10% to 15% or 16%. So try to understand it now –
As you know (A) = P ( 1+ r/100)t
So suppose (r) = 10% and (t) = 2 years then the value of ( 1+ r/100)t
= (1+10/100)2 which gives (110/100)2
Now use trick to find the square of 110 –
(110)2 = 112 x 100 = 12100 (this was easy… right)
(111)2 = Add 11 to 111= 122 and now add square of 11(121) to the only last digit (digit on once place) of 122 i.e., in 2 which gives answer = 12321
(112)2 = Add 12 to 112 = 124. Add square of 12(144) to the only last digit of 124 i.e. in 4 which gives = 12544
(116)2 = Add 16 to 116 = 132. Now add square of 16(256) to the last digit of 132 i.e. in 2. Answer = 13456
So the value of (116/100)2 = 1.3456
Now if you want to find Amount then just multiply principal with 1.3456 and if it is asked only Compound Interest then just multiply the principal with 0.3456.
Hope you have cracked the trick now….if yes then it’ll be good for you to learn it!!
Cubes of 101 to 115 –
This one will help you when the TIME is given for 3 years i.e., (A) = (1+r/100)3
(101)3 =1030301. (Remember in cubes of 101 to 115 the answer will be always in seven digits numbers.)
You can find this answer in three small steps –
1. Multiply 3 in only last digit of 101 i.e. in 1. It gives 103
2. Multiply 03 ( from 103) in last digit of 101 i.e. in 1 again, it gives 03. Write it after the first step answer like-10303
3. Now you got 5 digits and only two digits are left. In this last step write the cube of last digit of 101 which gives 1 and add 0 before it i.e. 01 and write it after the second step answer i.e. 1030301. This is your answer.
Well, I am not going to start it from 101 but from 110 because normally the interest rates are given in
the question from 10% to 15% or 16%. So try to understand it now –
As you know (A) = P ( 1+ r/100)t
So suppose (r) = 10% and (t) = 2 years then the value of ( 1+ r/100)t
= (1+10/100)2 which gives (110/100)2
Now use trick to find the square of 110 –
(110)2 = 112 x 100 = 12100 (this was easy… right)
(111)2 = Add 11 to 111= 122 and now add square of 11(121) to the only last digit (digit on once place) of 122 i.e., in 2 which gives answer = 12321
(112)2 = Add 12 to 112 = 124. Add square of 12(144) to the only last digit of 124 i.e. in 4 which gives = 12544
(116)2 = Add 16 to 116 = 132. Now add square of 16(256) to the last digit of 132 i.e. in 2. Answer = 13456
So the value of (116/100)2 = 1.3456
Now if you want to find Amount then just multiply principal with 1.3456 and if it is asked only Compound Interest then just multiply the principal with 0.3456.
Hope you have cracked the trick now….if yes then it’ll be good for you to learn it!!
Cubes of 101 to 115 –
This one will help you when the TIME is given for 3 years i.e., (A) = (1+r/100)3
(101)3 =1030301. (Remember in cubes of 101 to 115 the answer will be always in seven digits numbers.)
You can find this answer in three small steps –
1. Multiply 3 in only last digit of 101 i.e. in 1. It gives 103
2. Multiply 03 ( from 103) in last digit of 101 i.e. in 1 again, it gives 03. Write it after the first step answer like-10303
3. Now you got 5 digits and only two digits are left. In this last step write the cube of last digit of 101 which gives 1 and add 0 before it i.e. 01 and write it after the second step answer i.e. 1030301. This is your answer.
(102)3 = 102 x 3 (in just last digit) =106.
06 x 2 = 12 = 10612 Cube of 2 = 8 i.e. 08 = 1061208 (answer) (103)3 = 103 x 3 = 109 09 x 3 = 27 = 10927 (3)3 = 27 = 1092727 (answer) (104)3 = 104 x 3 = 112 12 x 4 = 48 = 11248 (4)3 = 64 = 1124864 (answer) (105)3 = 105 x 3 = 115 15 x 5 = 75 = 11575 (5)3 = 125 = 1157625 ( add 1 of 125 to just last digit of 11575) (106)3 = 106 x 3 = 118 18 x 6 = 108. Now add 1 of 108 to the last digit of 118, it gives 11908 (6)3 = 216. Add 2 of 216 to the last digit of 11908, it gives 1191016(answer) (109)3 = 109 x 3 = 127 27 x 9 = 243. Add 2 of 243 to last digit of 127 = 12943 (9)3 = 729. Add 7 of 729 to the last digit of 12943 = 1295029(answer) |
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(111)3 = 111 x 3 = 133
33 x 11 = 363. Add 3 from 363 in last digit of 133 = 13663
(11)3 = 1331.
As you already got 5 digits so you need only 2 digits but you have 4 digits in your hand i.e. 1331 so now add 13 from 1331 to the last two digits of 13663 and it gives 1367631(answer).
(115)3 = 115 x 3 = 145
45 x 15 = 675. Add 6 from 675 to the last digit of 145 = 15175
(15)3 = 3375. Add 33 from 3375 to the last two digit of 15175 = 1520875 (answer)
So the value of (115/100)3 = 1.520875.
33 x 11 = 363. Add 3 from 363 in last digit of 133 = 13663
(11)3 = 1331.
As you already got 5 digits so you need only 2 digits but you have 4 digits in your hand i.e. 1331 so now add 13 from 1331 to the last two digits of 13663 and it gives 1367631(answer).
(115)3 = 115 x 3 = 145
45 x 15 = 675. Add 6 from 675 to the last digit of 145 = 15175
(15)3 = 3375. Add 33 from 3375 to the last two digit of 15175 = 1520875 (answer)
So the value of (115/100)3 = 1.520875.