Question Number 159750 by greg_ed last updated on 20/Nov/21
$$\boldsymbol{\mathrm{Prove}}\:\boldsymbol{\mathrm{that}}\: \\ $$$$\:\sqrt{\mathrm{689}×\mathrm{690}×\mathrm{691}+\mathrm{1}}\:\boldsymbol{\mathrm{is}}\:\boldsymbol{\mathrm{a}}\:\boldsymbol{\mathrm{naturel}}\:\boldsymbol{\mathrm{number}}. \\ $$
Commented by Rasheed.Sindhi last updated on 20/Nov/21
$${Pl}\:{check}\:{the}\:{question},\:\sqrt{\mathrm{689}×\mathrm{690}×\mathrm{691}+\mathrm{1}}\: \\ $$$${is}\:{not}\:{a}\:{natural}\:{number}. \\ $$