Q1: Verify whether 17 is cube root of 4910 or not.
Ans: Here we need to check, 17 x 17 x 17 = 4910 or not.
17 = 1 + 7 = 8
So, 8 x 8 x 8 = 256
Now, we find digit sum of 256
256 = 13 = 4
Similarly, 4910 = 14 = 5
As, digit of both the side is not same, so even without solving sum we can say that,
17 is not the cube root of 4910.
Q2: Verify 6522 = 425114 or not.
Ans: 625 = 13 = 4
So, digit sum of 6522 is,
4 x 4 = 16 = 7
Now value of 425114 is,
4 + 2 + 5 + 1 + 1 + 4 = 8
As both the digits are not match, so answer is wrong.
Q3: Verify that 25 is square root of 625 or not.
Ans: Here we apply method of multiplication as
We need to check, 25 x 25 = 625 or not.
First, we find Digit sum of 25 × 25.
25 = 7
So, 7 x 7 = 49 = 13 = 4
Digit sum of 625 = 13 = 4
As digit of both the side is 4, means 25 is square root of 625.
Q4: Verify whether the following answer is correct or not without actual calculation.
900 divide by 120 gives Q =7 & R = 60.
Ans: Dividend, 900 = 9
Divisor, 120 = 3
Q = 7
R = 60 = 6
Dividend = 3 x 7 + 6 = 27 = 9
Both the answer is 9, so without doing actual calculation we can say that the answer is correct.
Q5: Verify whether the following answer is correct or not without actual calculation.
2795 ÷ 23, Q = 121, R = 12.
Ans: Dividend, 2795 = 5
Divisor, 23 = 5
Q, 121 = 4
R, 12 = 3
Put all the digit sum value in above formula,
Dividend = 5 x 4 + 3 = 23 = 5
Both the answer is same, means sum is correct.
Q6: Verify whether: 2435673 x 56442 =1374255466
Ans: 2435673 = 3 (Apply shortcut method)
56442 = 6 + 4 + 2 = 12 = 1 + 2 = 3
Multiply them,
3 × 3 = 9
1374255466 = 1 + 6 = 7 (apply shortcut method)
As both the answer different, means sum is wrong.
Q7: Verify whether: 0.45632 x 0.65432 = 0.2985793024
Ans: 0.45632 = 0.2
0.65432 = 0.2
Multiply them,
0.2 x 0.2 = 0.04
0.2985793024 = 0.04
As both the answer is same, means sum is correct.
Q8: Verify: 8938275 - 43525 = 8894750
Ans: 8938275 = 42
43525 = 19
Subtract final value of the number,
42 - 19 = 23 = 2 + 3 = 5
8894750 = 41 = 4 + 1 = 5
Both the answer is, 5 Means sum is correct.
Q9: Verify: 2612 -1201 = 1411
Ans: 2612 = 11 (Here we take 11, because if we shorten it then digit is 2, & in subtraction we will get negative number.)
1201 = 4
Now, we subtract final value,
11 - 4 = 7
Digit sum of answer is,
1411 = 1 + 4 + 1 + 1 = 7
Both the answer is 7.
Q10: Verify whether: 23197534 + 35672309 + 2347920 = 59104635
Ans: 23197534 = Here we ignore the 9 & the digits whose addition is 9,
Add the remaining numbers,
3 + 1 + 3 = 7
Similarly,
35672309 = 5 + 3 + 0 = 8
2347920 = 0
Total of digit sum of numbers is,
7 + 8 + 0 = 15 = 1 + 5 = 6
Now, find value of answer,
59104635 = 1 + 0 + 5 = 6
As, both digit is 6 means our answer is correct.
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