Question

Write the greatest whole number that uses all the digits from 1 to 9.

Answer 1

987,654,321 would be the greatest WHOLE number using the digits 1-9 only once i assume

Answer 2

we know that

The way to form the greatest number is to use the highest valued digit in the most significant digit.

so

$900,000,000+80,000,000+7,000,000+600,000+50,000+4,000+300+20+1=987,654,321$

therefore

the answer is

The greatest whole number that uses all the digits from 1 to 9 only at once is

$987,654,321$