SEAMC Published Shorts


The problems in this collection have been adapted from problems that have been set in South East Asian Mathematics Competitions


Megabytes and Kilobytes

Age 11 to 14 Short Challenge Level:

How many bytes are there in one megabyte?

Identical Digit Multiplication

Age 11 to 14 Short Challenge Level:

77 is multiplied by another two-digit number with identical digits. What is the product?

Smallest Fraction

Age 11 to 14 Short Challenge Level:

Which of these is the smallest?

Cuboid Faces

Age 11 to 14 Short Challenge Level:

Can you find the volume of a cuboid, given the areas of its faces?

Sum and Differences

Age 11 to 14 Short Challenge Level:

Three numbers add up to 100. The difference between the larger two is 12 and the difference between the smaller two is 2. What are the numbers?

Choose the Mean

Age 11 to 14 Short Challenge Level:

Find 4 numbers which have a mean of 7, a median of 8 and a mode of 9.

Giant Rubik's Cube

Age 11 to 14 Short Challenge Level:

How many cubes would be visible in a 12 by 12 by 12 Rubik’s cube?

Hot Dogs

Age 11 to 14 Short Challenge Level:

How many hot dogs did this hot dog lover eat on the first day of her binge?

Roses and Carnations

Age 11 to 14 Short Challenge Level:

How many different bunches of flowers can this class buy for their teacher?

Strange Dice

Age 11 to 14 Short Challenge Level:

If two of these unusually numbered dice are thrown, how many different sums are possible?

2014 Even Numbers

Age 11 to 14 Short Challenge Level:

What is the difference between the sum of the first 2014 odd numbers and the sum of the first 2014 even numbers?

Multiplication Cube

Age 11 to 14 Short Challenge Level:

The net shown is folded up to form a cube. What is the largest possible vertex product?

Adding and Multiplying

Age 11 to 14 Short Challenge Level:

Amy misread a question and got an incorrect answer. What should the answer have be?

Speed over a Bridge

Age 11 to 14 Short Challenge Level:

How fast is the train travelling as it goes over the bridge?

Draining a Pool

Age 11 to 14 Short Challenge Level:

The water is being drained from a pool. After how long will the depth of the pool be 144 cm?

Overlapping Beer Mats

Age 11 to 14 Short Challenge Level:

Can you find the area of the overlap when these two beer mats are placed on top of each other?

Nested Squares

Age 11 to 14 Short Challenge Level:

What proportion of the diagram is shaded?

Reverse Ages

Age 11 to 14 Short Challenge Level:

When is the next time that Brian's age will be the reverse of his father's age?

Bouncing Ball

Age 11 to 14 Short Challenge Level:

A ball is dropped from a height, and every time it hits the ground, it bounces to 3/5 of the height from which it fell.

Fraction of a Square

Age 11 to 14 Short Challenge Level:

What fraction of this square is shaded?

Split Clock Face

Age 11 to 14 Short Challenge Level:

Use 2 straight lines to split the clock face into 3 parts so that the sums of the numbers in each of the parts are equal.

Mean Balance

Age 11 to 14 Short Challenge Level:

Given information about the mean, can you work out the missing numbers?

Dance Party

Age 11 to 14 Short Challenge Level:

At a party, each man danced with exactly three women, and each woman danced with exactly two men. If 12 men attended the party, how many women attended?

Missing Digits

Age 11 to 14 Short Challenge Level:

Can you find the missing digits in this calculation?

Range of Averages

Age 11 to 14 Short Challenge Level:

Find these 4 numbers, given their mode, median and range.

Divisible Digits

Age 11 to 14 Short Challenge Level:

Can you find the missing digits, given that the number is divisible by 3, 4, 5 and 6?

Square Within a Square Within...

Age 11 to 14 Short Challenge Level:

What fraction of this square is shaded?

Palindromic Milometer

Age 11 to 14 Short Challenge Level:

At the beginning and end of Alan's journey, his milometer showed a palindromic number. Can you find his maximum possible average speed?

Shifting Average

Age 11 to 14 Short Challenge Level:

What happens to the average if you subtract 8 from all of the numbers?

Square Grid

Age 11 to 14 Short Challenge Level:

Can you work out what fraction of this grid is shaded?

Clubs

Age 11 to 14 Short Challenge Level:

How many students are in the maths club and the science club?

Tilted Tank

Age 11 to 14 Short Challenge Level:

Can you find the height of the water in this tilted tank when it is flat?

The Average Age

Age 11 to 14 Short Challenge Level:

Given this information about averages, find the ages of these teachers.

Brothers and Sisters

Age 11 to 14 Short Challenge Level:

Can you work out how many brothers and sisters are in the family?

Between a Sixth and a Twelfth

Age 11 to 14 Short Challenge Level:

The space on a number line between a sixth and a twelfth is split into 3 equal parts. Find the number indicated.

The Elephant Diet

Age 11 to 14 Short Challenge Level:

Use the relationship between the elephant and the rabbit to find out how many carrots the rabbit eats in a day

Average Temperature

Age 11 to 14 Short Challenge Level:

The average temperature of six cities is 5$^\circ$C. What is the average temperature when two cities are added?

Sum of 1s

Age 11 to 14 Short Challenge Level:

Can you find the last 5 digits of this sum?

Multiplication Mistake

Age 11 to 14 Short Challenge Level:

Jane accidentally multiplied by 54 instead of 45, and her answer was 198 too big. What number did she multiply 54 by?

Diagonal Side

Age 11 to 14 Short Challenge Level:

Can you work out the area of a square drawn on a diagonal?

Dividing a Square

Age 11 to 14 Short Challenge Level:

A square is divided into three shapes which all have equal areas. Can you find the length of this side?

Missing 9s

Age 11 to 14 Short Challenge Level:

Sara makes a list of the whole numbers that do not contain any 9s. What is the 300th number on her list?

Lattice Points on a Line

Age 11 to 14 Short Challenge Level:

How many lattice points are there in the first quadrant that lie on the line 3x + 4y = 59 ?

Graph Area

Age 11 to 14 Short Challenge Level:

Can you find the area between this graph and the x-axis, between x=3 and x=7?

French Test

Age 11 to 14 Short Challenge Level:

What was the average score in this French test?

Charlie's Money

Age 11 to 14 Short Challenge Level:

How much money did Charlie have to begin with?

Red Card Blue Card

Age 11 to 14 Short Challenge Level:

Can you arrange the red and blue cards so that the rules are all followed?

Inches and Barleycorns

Age 11 to 14 Short Challenge Level:

How many barleycorns are there in one inch?

Scalene Area

Age 11 to 14 Short Challenge Level:

Can you find the area of this scalene triangle?

Number of Arms

Age 11 to 14 Short Challenge Level:

What is the probability that the next person you meet has an above average number of arms?

Committees

Age 11 to 14 Short Challenge Level:

Every member of the club is a member of two committees. How many members are there in the club?

Packing Small Boxes

Age 11 to 14 Short Challenge Level:

How many small boxes will fit inside the big box?

Which Face?

Age 11 to 14 Short Challenge Level:

Which faces are opposite each other when this net is folded into a cube?

Cuboid Perimeters

Age 11 to 14 Short Challenge Level:

Can you find the volume of a cuboid, given its perimeters?

Tile Border

Age 11 to 14 Short Challenge Level:

What is the largest possible number of yellow tiles in this pattern?

Tiled Floor

Age 11 to 14 Short Challenge Level:

This tiled floor has 109 purple tiles. How many tiles are there altogether?

Leap Monday

Age 11 to 14 Short Challenge Level:

Can you find the next time that the 29th of February will fall on a Monday?

Tricky Fractions

Age 11 to 14 Short Challenge Level:

Use this series of fractions to find the value of x.

Black and Gold Storeys

Age 11 to 14 Short Challenge Level:

25 of the storeys of a 50 storey building are painted gold, and the rest are painted black...

Washing Elephants

Age 11 to 14 Short Challenge Level:

How long will it take Mary and Nigel to wash an elephant if they work together?

Last Digit

Age 11 to 14 Short Challenge Level:

What is the last digit in this calculation involving powers?

Linear Area

Age 11 to 14 Short Challenge Level:

Find the area of the triangle enclosed by these lines.

Rain

Age 11 to 14 Short Challenge Level:

How many dry days did Aisha have on her holiday?

Clock Angle

Age 11 to 14 Short Challenge Level:

What is the angle between the the hands of a clock at 8:24?

Add All the Angles

Age 11 to 14 Short Challenge Level:

Find the sum of all of the angles denoted by letters in this diagram

Power up to 1000

Age 14 to 16 Short Challenge Level:

Find $x+y$, where $2^x\times5^y=1000$

Cones and Spheres

Age 14 to 16 Short Challenge Level:

A solid metal cone is melted down and turned into spheres. How many spheres can be made?

Square to a Rectangle

Age 14 to 16 Short Challenge Level:

Kevin has moved some tiles to change the shape of his patio from a square to a rectangle. What are the lengths of the sides of the rectangle?

Bobbly Perimeter

Age 14 to 16 Short Challenge Level:

Find the perimeter of this shape made of semicircles

Ratio of Areas

Age 14 to 16 Short Challenge Level:

What is the ratio of the area of the hexagon to the area of the triangle?

Flipping Coins

Age 14 to 16 Short Challenge Level:

A coin is flipped 4 times. What is the probability of getting heads at least 3 times?

The Power of the Sum

Age 14 to 16 Short Challenge Level:

What is this sum, expressed as a power of 2?

Rough Rectangle

Age 14 to 16 Short Challenge Level:

What is the smallest possible area that this rectangle could have?

Root 2017

Age 14 to 16 Short Challenge Level:

Between which two whole numbers is $\sqrt{2017}$ $?$

Cat on a Wall

Age 14 to 16 Short Challenge Level:

How high is the wall that this cat is lying on?

Similar Perimeter

Age 14 to 16 Short Challenge Level:

What is the smallest possible perimeter of the larger triangle described?

Table Total

Age 14 to 16 Short Challenge Level:

Can you find the sum of all of the numbers in the table?

Length, Width and Area

Age 14 to 16 Short Challenge Level:

The area of a rectangle is 225 square units. Find its width.

Power of 3

Age 14 to 16 Short Challenge Level:

What power of 27 is needed to get the correct power of 3?

Square Overlap

Age 14 to 16 Short Challenge Level:

The top square has been rotated so that the squares meet at a 60$^\text{o}$ angle. What is the area of the overlap?

Doubly Isosceles

Age 14 to 16 Short Challenge Level:

Find the missing distance in this diagram with two isosceles triangles

Growing Triangle

Age 14 to 16 Short Challenge Level:

If the base and height of a triangle are increased by different percentages, what happens to its area?

XOXOXO

Age 14 to 16 Short Challenge Level:

6 tiles are placed in a row. What is the probability that no two adjacent tiles have the same letter on them?

Square in a Circle in a Square

Age 14 to 16 Short Challenge Level:

What is the ratio of the areas of the squares in the diagram?

Thousands of X

Age 14 to 16 Short Challenge Level:

Can you solve this scary-looking equation?

Traffic Tunnel

Age 14 to 16 Short Challenge Level:

Will these vehicles fit through this tunnel?

Snapped Palm Tree

Age 14 to 16 Short Challenge Level:

A palm tree has snapped in a storm. What is the height of the piece that is still standing?

Fraction of Percentages

Age 14 to 16 Short Challenge Level:

What is $W$ as a fraction of $Z?$

Odd Dice

Age 14 to 16 Short Challenge Level:

These strange dice are rolled. What is the probability that the sum obtained is an odd number?

3-4-5 Circle

Age 14 to 16 Short Challenge Level:

Can you find the radius of the circle inscribed inside a '3-4-5 triangle'?

Roots Near 9

Age 14 to 16 Short Challenge Level:

For how many integers 𝑛 is the difference between √𝑛 and 9 is less than 1?

Swapping Sweets

Age 14 to 16 Short Challenge Level:

If two girls each take a sweet from each other's bags, what is the probability that they end up with what they started with?

Strike a Chord

Age 14 to 16 Short Challenge Level:

Can you work out the radius of a circle from some information about a chord?

Rough Root

Age 14 to 16 Short Challenge Level:

Which of these options is closest to this square root?

Black and White Socks

Age 14 to 16 Short Challenge Level:

There are 20 black socks and some white socks in a drawer. Can you work out how many of the socks are white?

Difference Sequence

Age 14 to 16 Short Challenge Level:

When will 2000 appear in this sequence?

Slide Height

Age 14 to 16 Short Challenge Level:

How high is the top of the slide?

Coal Truck

Age 14 to 16 Short Challenge Level:

What percentage of the truck's final mass is coal?

Clever Calculation

Age 14 to 16 Short Challenge Level:

Find the shortcut to do this calculation quickly!

Big Product

Age 14 to 16 Short Challenge Level:

How many digits are there in this product?