ABACUS International Math Challenge
for
3rd and 4th graders
September, 2005
A.489. 28 monies live on an island. Some
of them are jumping on trees, a few of them are playing on ropes, and the
others are resting on the grass. There are a total of 19 monies on the trees
and on the ropes. I counted a total of 17 of them on the trees and in the
grass. How many monies are there on the trees, how many on the ropes and
how many in the grass?
A.490. A friend of mine has a few ostriches
and zebras in his garden. When I visited him last, I counted a total of
18 animal heads and 46 animal legs. How many of each animal does my friend
have?
A.491. In a zoo the caretaker of the seals
stores the following amounts of fish in 8 different boxes: 3 kg; 14 kg;
18 kg; 22 kg; 27 kg; 32 kg; 36 kg and 60 kg. Today he is planning to give
them 80 kg of fish. Which boxes should he carry out to the seal pool if
he wants to carry the least number of boxes and exactly 80 kg of fish?
A.492. The fourth grade is going on a school
trip. Every student had to bring in $64 for the trip to cover all costs.
Unfortunately, 3 students could not participate on the trip. Therefore,
every student who went on the trip had to bring in $4 more so those who
did not go could get their money back. How many students went on the trip?
A.493. The farmer separates his pigs and
piglets into 3 different pig sties. 10 pigs have 1 piglet each, 10 pigs
have 2 piglets each, and 10 pigs have 3 piglets each. How should he divide
the animals if he wants to have the same number of animals in each sty,
but he does not want to separate any piglet from his mom?
A.494. If 5 elephants eat 10 stacks of
hay in 6 days, then:
a) how many stacks of hay do 8 elephants eat in 12 days;
b)how long does it take 3 elephants to eat 60 stacks of hay;
c) how many elephants can eat 18 stacks of hay in 9 days?
A.495. A snapping turtle and a painted
turtle start to go down to the lake at the same time. The snapping turtle
is 80 meters from the lake, and he can crawl 125 cm every 5 minutes. The
painted turtle is 16 meters further away from the lake, but he can crawl
12 dm every 4 minutes. Which turtle reaches the lake first if they keep
on going by their own speeds and never rest?
A.496. The weight of 12 kangaroos is the
same as the weight of 3 giraffes, the weight of 20 deer is the same as the
weight of 2 hippopotamus, and the weight of 2 deer is the same as the weight
of 1 giraffe.
a) How many kangaroos have the same weight as 8 giraffes?
b) How many deer have the same weight as 5 hippopotamus?
c) How many giraffes have the same weight as 6 hippopotamus?
Please, send your solutions to: