ABACUS International Math Challenge
for
3rd and 4th graders
December, 2007
A.609. The carpenters are cutting 6-meter
long beams. It takes 3 minutes to saw a beam once. How long does it take
to cut 10 beams into half-meter long pieces?
A.610. How could you measure 13 minutes
with the help of a 7-minute and a 5-minute sand clock?
A.611. Three workers: a cabinet maker,
a painter, and a carpenter live in the same town. Their names (not necessarily
in that order) are Peter, Ben and Sam. Not too long ago the painter wanted
to ask his friend, the cabinet maker, to make some furniture for him. He
learned that the cabinet maker is working at the house of the carpenter.
Who has what profession if we know that Ben has never heard of Peter?
A.612. Camille's dad is putting new tiles
on their kitchen floor: dark brown tiles in two rows around the edges, and
light brown tiles in the middle. The tiles are 20cm x 20cm squares. How
many dark brown tiles does he need if the dimensions of the rectangular
kitchen are 3m 2dm x 4m 4dm?
A.613. Some 3-digit numbers when multiplied
by 4 give a 4-digit number. How many such 3-digit numbers are there?
A.614. A potter is making mugs for the
county fair. Since he is in a rush, he makes a lot of mistakes. A tenth
of the mugs he made in a week are chipped, and a quarter of them are scratched.
On top of these, 10 mugs are chipped and scratched, as well. Luckily, he
could fix those that are only scratched. This way he managed to take 80
mugs to the fair. How many mugs did he make in total?
A.615. Tom is making legs for 174 four-legged
tables. He has done 116 legs so far, and used 6.5 liters of paint to stain
them. How many more legs does he need to make, and how many half-liter cans
of paint does he still need to stain them?
A.616. In my school's Talent Show 57 productions
were signed up by the students this year. We needed 3 days to see them all.
If they put 7 productions from the first day to the second day then all
three days would have had the same number of productions. Belle was able
to attend only the first 2 days. How many productions did she see?
Please, send your solutions to: