Question Number 73847 by mr W last updated on 16/Nov/19
Commented by mr W last updated on 16/Nov/19
$${repost}\:{of}\:{an}\:{old}\:{question}\:{which}\:{is} \\ $$$${already}\:{deleted}. \\ $$
Commented by JDamian last updated on 16/Nov/19
$$\mathrm{I}\:\mathrm{find}\:\mathrm{it}\:\mathrm{confusing}\:\:\mathrm{because}\:\mathrm{of}\:\mathrm{the}\:\mathrm{overuse} \\ $$$$\mathrm{of}\:\mathrm{the}\:\mathrm{word}\:\boldsymbol{\mathrm{number}} \\ $$
Commented by mr W last updated on 16/Nov/19
$${but}\:{we}\:{can}\:{understand}\:{what}\:{is}\:{meant}.\: \\ $$
Commented by mr W last updated on 16/Nov/19
$${A}={numbers}\:{in}\:{which}\:{each}\:{digit}\:{occurs} \\ $$$${twice} \\ $$$${B}={numbers}\:{containing}\:\mathrm{4}\:{digits} \\ $$$${C}={numbers},\:{the}\:{sum}\:{of}\:{whose}\:{digits} \\ $$$${is}\:\mathrm{8} \\ $$