ABACUS International Math Challenge
for
3rd and 4th graders
January, 2001
A.225. There are walnuts on each of three
plates: 22 on one of them, 14 on another, and 12 on the third plate. As
a step, from one plate you may put exactly as many walnuts onto another
plate as many walnuts there are already on this other plate. Can you have
the same number of walnuts on each plate after three steps?
A.226. You have four red and four blue
pearls. Using all of them, how many different necklaces can you make out
of them? (After you put all the pearls on the line, you tie the ends so
that the pearls may slide around freely.)
A.227. Look at the following diagram of
a square with its diagonals, and with the segments connecting the midpoints
of the opposite sides. How many triangles can you see on the diagram?
A.228. If 3 red dots are worth 6 green
squares, and 3 green squares are worth 15 blue stars, then how many blue
stars will one red dot be worth?
A.229. If a brick is 2 kilograms and a
half brick, then how many kilograms are 2 bricks?
A.230. In a parking lot there are cars
with four wheels, motorcycles with 2 wheels, and mopeds with three wheels.
The 15 vehicles have a total of 56 wheels. How many cars are there in this
parking lot?
A.231. Write addition, subtraction, multiplication
signs or nothing between the digits 123456789 so that the equality is true:
123456789=2001
by Mary Panchenko
A.232. How many 3-digit positive whole
numbers are there in which the sum of the digits is odd, and when you add
one to the 3-digit number, the sum of the digits of the new number remains
odd?
Please, send your solutions to: