Question

the square of a number has four digits.one of its digits is 0 and other three digits are even. if the square of the number is less than 7000.find the number​

Answer 1

Answer:

If the square of the number is less than 7000 then the number is 78. we can also skip checking 50, 60, 70 and 80 because we know the square will end in two zeros. You can also skip 56 to 62 and 72 to 76 because their squares start with an odd number.