Question
Using the method of successive subtraction examine whether or not the following numbers are perfect cubes: $792$
✓
Answer
Applying subtraction method, We have, $792 - 1 = 791$
$ 791 - 7 = 784$
$ 784 - 19= 765$
$ 765 - 37 = 728$
$ 728 - 61 = 667$
$ 667 - 91 =576$
$ 576 - 127 = 449$
$ 449 - 169 = 280 $
$280 - 217 = 63$
$\because$ Next number to be subtracted is $271,$ which is greter than $63$ Hence, $792$ is not a perfect cube
$ 791 - 7 = 784$
$ 784 - 19= 765$
$ 765 - 37 = 728$
$ 728 - 61 = 667$
$ 667 - 91 =576$
$ 576 - 127 = 449$
$ 449 - 169 = 280 $
$280 - 217 = 63$
$\because$ Next number to be subtracted is $271,$ which is greter than $63$ Hence, $792$ is not a perfect cube
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