ABACUS International Math Competition
for
3rd and 4th graders
December, 1997
A.25. By recognizing some kind of a logical
pattern, continue the following sequence:
A.26. The diagram indicates a land with
four wells on it. Divide this land into four parts that have the same size
and same shape with one well on each part.
A.27. The diagram indicates a land with
four wells on it. Divide this land into four parts that have the same size
and same shape with one well on each part.
A.28. In this addition same letters mean
same digits, different letters mean different digits. What number is ABC?
A.29. Smarty is thinking: what could the
greatest difference be between such two 3-digit numbers that differ only
in the order of their digits?
Help this kid.
A.30. There are 5 cabinets along one wall
of a rectangular shaped room in the following order: A, B, C, D, and E.
The key to cabinet A opens cabinet E, you can open cabinet C with the key
to cabinet B, and every key opens at least one of the neighboring cabinets,
also. At least how many keys do you need to open all the cabinets?
A.31. We took the labels off of five different
soft drink bottles. Each of 10 players put the labels back in some order.
Everybody got at least one match. (In other words: Every player put back
at least one label correctly.) 3 players got exactly 1 match, 2 players
got 2, and 2 players got 3 matches. How many players got 4 and how many
got 5 matches?
A.32. Algae is growing on the surface of
a lake. The area the algae covers doubles every day. On the 32nd day the
whole lake got covered. On which day was half of the lake covered?
Please, send your solutions to:
Solutions of previous
problems