The first digit of a 4 digit number is 7 and the last digit is 4. If the first and last digits are swapped, then the new number would be:
a)made larger by 2997
b)made smaller by 2997
c)made larger by 3003
d)not enough information
The first digit of a 4 digit number is 7 and the last digit is 4. If the first and last digits are swapped, then the new number would be:
a)made larger by 2997
b)made smaller by 2997
c)made larger by 3003
d)not enough information
Hello, kl050196!
Set up the subtraction problem . . .The first digit of a four- digit number is 7 and the last digit is 4.
If the first and last digits are swapped, then the new number would be:
(a) made larger by 2997
(b) made smaller by 2997
(c) made larger by 3003
(d) not enough information
The number has the form: .$\displaystyle 7\,a\,b\,4$
The new number would be: .$\displaystyle 4\,a\,b\,7$
Obviously, the number becomes smaller . . . Eliminate choices (a) and (c).
Then we have: .$\displaystyle \begin{array}{ccccc}& 7 & a & b & 4 \\ - & 4 & a & b & 7 \\ \hline
& ? & ? & ? & ?
\end{array}$
The last (rightmost) digit is 7.
The next digit is 9 . . . [Think about it!]
The next digit is 9.
And the leftmost digit is 2.
The difference is 2997 . . . answer (b).