13 and 31 is a strange pair of numbers such that their squares 169 and 961 are also mirror images of each other. Can you find two other such pairs? 1. Quick Tricks. Let me teach you Alright Geeta. a trick, Karan. Pick any 2-digit number ending in 5. Take the tens part Tens part of 45 is 4. of the number and Its successor is 5, multiply it with so 4 × 5 = 20. its successor. Now prefix this Square of 5 is 25, so number to the number obtained square of 5. is 2025. MATHEMATICS UNIT-3 Good. Check it by actual The square is correct. multiplication. Friends, you can also try this trick for 425 or 705 or any other 3-digit number ending in 5. You will definitely enjoy it. Geeta, now let me teach you one trick. This trick can help Sure you to find the cube root n of any 4, 5 or 6-digit perfect cube orally. Alright. But what do we have to Pick any 4, 5 or 6 n1 do for it? digit perfect cube. From the right put a 91125 comma after 3 digits. 91, 125 See the digit at the units place and find the units place of its cube. SQUARE-SQUARE ROOT AND CUBE-CUBE ROOT 99 MATHEMATICS Digit at units Good! This number is place is 5 and digit the digit at units place at ones place of of the cube root. Now its cube see the digits before is also 5. the comma. Ascertain which 91 number's cube is less than this number. The cube of 4 is Absolutely. This is the 64 which is less digit at the tens place than 91. of the cube root. So it means You are right. that the cube root is 45. Friends, you can also try the same for Fascinating! 13824, 2197, 50653 or any other perfect cube of 4, 5 or 6 digit. Bye for now! 2. Cross Number Puzzle Down 1. Cube of 9. 2. Missing number to make 12, ____, 37, a pythagorean triplet. 4. Smallest number by which 248 be multiplied to make the resultant a perfect cube number. 5. Square of 75. 6. Smallest square number that is divisible by each of 5 and 11 9. Without adding, find the sum of 1 + 3 + 5 + 7 + 9 + 11. 10. Smallest number which when added to 7669 makes the resultant a perfect square. Across 2. Square of 19. 3. Look at the numbers given below and find the number which cannot be a perfect square. 81, 100, 144, 25000 7. Square root of 4489 8. Smallest natural number other than 1 which is a perfect square as well as a perfect cube number. 10. Cube root of 357911. 11. Smallest number which when subtracted from 374695 makes the resultant a perfect square number. MATHEMATICS Rough Work UNIT-3 Rough Work SQUARE-SQUARE ROOT AND CUBE-CUBE ROOT 103 MATHEMATICS Rough Work
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12, 21, 102, 201 Cross Number Puzzle