ABACUS International Math Challenge
for
3rd and 4th graders
October, 2000
A.201. Find the greatest 5-digit number
in which every digit is greater than the sum of the digits behind it.
A.202. Find four different digits that
allow you to write three 4-digit numbers (using all four digits in every
number) so that the sum of two of these numbers is the third number.
A.203. In the following multiplication
we know only one digit. The other digits marked by the letter "a"
are not necessarily the same digits. Find all the other digits.
A.204. You may write the numbers 2, 5,
or 10 in the empty fields of the following grid. Fill in the blanks so that
the sums of the numbers in each column and row is 22. Find all the possible
solutions.
A.205. Is it possible to write the numbers
1, 2, 3, 4, 5, 6, 7, and 8 into the empty squares so that no two squares
connected contain consecutive numbers?
A.206. Write the numbers 1, 2, 3, 4, 5,
6, 7, 8, and 9 into the empty squares so that the sum of the two numbers
in the squares connected by a line is the number written on that line.
A.207. How many different license plates
can be made using 3 letters and 3 digits if the first three characters are
letters and the last three characters are numbers? (You may use 25 different
letters, and any of the 10 digits!)
A.208. There are 12 girls and 15 boys participating
in a school party. How many different ways can you pick 4 pairs of dancing
partners out of them?
Please, send your solutions to: