List

Equations and Formulae - Short Problems



This is part of our collection of Short Problems.

You may also be interested in our longer problems on Equations and Formulae  Age 11-14 and Age 14-16.

Printable worksheets containing selections of these problems are available here.

Small pepper seedlings in orange pots.
problem

Five-To

Age
11 to 14
Challenge level
1 out of 3

The number 2005 is the sum of a sequence of five consecutive positive integers. What is the smallest of these integers?

Small pepper seedlings in orange pots.
problem

Luis' Eight

Age
11 to 14
Challenge level
1 out of 3

Luis writes down eight consecutive positive integers. The sum of the three smallest numbers is 33. What is the sum of the three largest numbers?

Small pepper seedlings in orange pots.
problem

Shape Sums

Age
11 to 14
Challenge level
1 out of 3

Given some relationships amongst these shapes, how many triangles equal one diamond?

Small pepper seedlings in orange pots.
problem

Partial Magic

Age
11 to 14
Challenge level
1 out of 3

This magic square has only been partially completed. Can you still solve it...

Small pepper seedlings in orange pots.
problem

Interstellar

Age
11 to 14
Challenge level
1 out of 3

What number could replace x so that x/5 is between 3 and 4?

Small pepper seedlings in orange pots.
problem

Seven Dwarfs

Age
11 to 14
Challenge level
1 out of 3

The Seven Dwarfs have seven different birthdays. How old can they be?

Small pepper seedlings in orange pots.
problem

Symbol

Age
11 to 14
Challenge level
2 out of 3

Using the new operator $\oplus$, can you solve this equation?

Small pepper seedlings in orange pots.
problem

Fifty Coins

Age
11 to 14
Challenge level
2 out of 3

Cheryl finds a bag of coins. Can you work out how many more 5p coins than 2p coins are in the bag?

Small pepper seedlings in orange pots.
problem

Crossover

Age
11 to 14
Challenge level
2 out of 3

The numbers 2 to 8 are to be placed in the diagram so that the row and column each adds to 21. Which numbers can replace x?

Small pepper seedlings in orange pots.
problem

Geometric Quadrilateral

Age
11 to 14
Challenge level
2 out of 3

Each interior angle in a quadrilateral (apart from the smallest) is twice the previous one. What is the size of the smallest interior angle?

Small pepper seedlings in orange pots.
problem

Multiplication Mistake

Age
11 to 14
Challenge level
2 out of 3

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

Small pepper seedlings in orange pots.
problem

Turnips

Age
11 to 14
Challenge level
2 out of 3

Baldrick could buy 6 parsnips and 7 turnips, or 8 parsnips and 4 turnips. How many parsnips could he buy?

Small pepper seedlings in orange pots.
problem

Star Sum

Age
11 to 14
Challenge level
2 out of 3

You may have seen magic squares before, but can you work out the missing numbers on this magic star?

Small pepper seedlings in orange pots.
problem

Magic 7

Age
11 to 14
Challenge level
3 out of 3

Can you complete this magic square with the numbers from 7 to 15?

Small pepper seedlings in orange pots.
problem

To Run or Not to Run?

Age
11 to 14
Challenge level
3 out of 3

If an athlete takes 10 minutes longer to walk, run and cycle three miles than he does to cycle all three miles, how long does it take him?

Small pepper seedlings in orange pots.
problem

Named Products

Age
11 to 14
Challenge level
3 out of 3

Can you find the solution to this equation? Each of the different letters stands for a different number.

Small pepper seedlings in orange pots.
problem

Weighing the Baby

Age
14 to 16
Challenge level
1 out of 3

Weighing the baby at the clinic was a problem. Can you work out the weight of the baby from the information given?

Small pepper seedlings in orange pots.
problem

Adjacent Additions

Age
14 to 16
Challenge level
1 out of 3

In a 7-digit numerical code, each group of four consecutive digits adds to 16, and each group of five consecutive digits adds to 19. What is the sum of all 7 digits?

Small pepper seedlings in orange pots.
problem

In the Hundreds

Age
14 to 16
Challenge level
1 out of 3

For how many positive values of $n$ are both $\frac n2$ and $2n$ three-digit whole numbers?

Small pepper seedlings in orange pots.
problem

I Love Musical Stars

Age
14 to 16
Challenge level
1 out of 3

Each row and column has the total given. What is the value of the heart symbol?

Small pepper seedlings in orange pots.
problem

Table Total

Age
14 to 16
Challenge level
1 out of 3

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

Small pepper seedlings in orange pots.
problem

Symmetric Reasoning

Age
14 to 16
Challenge level
1 out of 3

Can you sum up the solutions to this equation?

Small pepper seedlings in orange pots.
problem

Pure Algebra

Age
14 to 16
Challenge level
1 out of 3

Can you work out the product of $a$ and $b$ from the information in the question?

Small pepper seedlings in orange pots.
problem

Bat and Ball

Age
14 to 16
Challenge level
1 out of 3

Can you work out how much this bat costs?

Small pepper seedlings in orange pots.
problem

Average Surroundings

Age
14 to 16
Challenge level
2 out of 3

Can you work out Ali's age based on the diagram?

Small pepper seedlings in orange pots.
problem

Sum = Product = Quotient

Age
14 to 16
Challenge level
2 out of 3

Can you find a pair of numbers such that their sum, product and quotient are all equal? Are there any other pairs?

Small pepper seedlings in orange pots.
problem

Reciprocal Values

Age
14 to 16
Challenge level
2 out of 3

Manipulate one algebraic fraction to solve another.

Small pepper seedlings in orange pots.
problem

Near 10

Age
14 to 16
Challenge level
2 out of 3

10 must remain within easy reach...

Small pepper seedlings in orange pots.
problem

Packing Boxes

Age
14 to 16
Challenge level
2 out of 3

Look at the times that Harry, Christine and Betty take to pack boxes when working in pairs, to find how fast Christine can pack boxes by herself.

Small pepper seedlings in orange pots.
problem

Alien Currency

Age
14 to 16
Challenge level
2 out of 3

The planet Zog has both green and blue bank notes. Can you work out how many zogs two green and three blue bank notes are worth?

Small pepper seedlings in orange pots.
problem

Algebraic Differences

Age
14 to 16
Challenge level
2 out of 3

If $6x-y=21$ and $6y-x=14$, what is the value of $x-y$?

Small pepper seedlings in orange pots.
problem

Well Read

Age
14 to 16
Challenge level
2 out of 3

If you know how many books each boy, girl and teddy bear borrowed from the library, can you work out the number of girls?

Small pepper seedlings in orange pots.
problem

Oldest and Youngest

Age
14 to 16
Challenge level
2 out of 3

Edith had 9 children at 15 month intervals. If the oldest is now six times as old as the youngest, how old is her youngest child?

Small pepper seedlings in orange pots.
problem

Tennis Training

Age
14 to 16
Challenge level
2 out of 3

After tennis training, Andy, Roger and Maria collect up the balls. Can you work out how many Andy collects?

Small pepper seedlings in orange pots.
problem

Relative Angles

Age
14 to 16
Challenge level
2 out of 3

Can you work out the angles of a triangle from the relationships between them?

Small pepper seedlings in orange pots.
problem

Square to a Rectangle

Age
14 to 16
Challenge level
2 out of 3

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?

Small pepper seedlings in orange pots.
problem

Black and White Socks

Age
14 to 16
Challenge level
2 out of 3

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

Small pepper seedlings in orange pots.
problem

Thousands of x

Age
14 to 16
Challenge level
2 out of 3

Can you solve this scary-looking equation?

Small pepper seedlings in orange pots.
problem
Favourite

Terminology

Age
14 to 16
Challenge level
2 out of 3

Given an equilateral triangle inside an isosceles triangle, can you find a relationship between the angles?

Small pepper seedlings in orange pots.
problem

Traffic Tunnel

Age
14 to 16
Challenge level
2 out of 3

Will these vehicles fit through this tunnel?

Small pepper seedlings in orange pots.
problem

Day of the Triffids

Age
14 to 16
Challenge level
2 out of 3

Jasmine buys three different types of plant. How many triffids did she buy?

Small pepper seedlings in orange pots.
problem

Fractions of Fractions

Age
14 to 16
Challenge level
2 out of 3

If you know that a fraction of X is the same as a different fraction of Y, can you work out X/Y?

Small pepper seedlings in orange pots.
problem

Table Height

Age
14 to 16
Challenge level
2 out of 3

A table has blocks of wood placed on and next to it. Can you work out how tall it is?

Small pepper seedlings in orange pots.
problem

Big Fish

Age
14 to 16
Challenge level
2 out of 3

Granny has taken up deep-sea fishing! Last week, she caught a fish so big that she had to cut it into three pieces in order to weigh it...

Small pepper seedlings in orange pots.
problem

Simultaneous Multiplying

Age
14 to 16
Challenge level
2 out of 3

If $a \times b=2$, $b \times c=24$, $c \times a=3$ and $a$, $b$ and $c$ are positive, what is the value of $a+b+c$?

Small pepper seedlings in orange pots.
problem

Monetary Difference

Age
14 to 16
Challenge level
2 out of 3

Al, Bertie, Chris and Di have sums of money totalling £150... What is the difference between the amount Al and Di have?

Small pepper seedlings in orange pots.
problem

Three Fruits

Age
14 to 16
Challenge level
2 out of 3

Quince, quonce and quance are three types of fruit. Can you work out the order of heaviness of the fruits?

Small pepper seedlings in orange pots.
problem

Weighing Scales

Age
14 to 16
Challenge level
2 out of 3

Can you work out how many spheres will balance a single pyramid?

Small pepper seedlings in orange pots.
problem

Nested Square Roots

Age
14 to 16
Challenge level
3 out of 3

Can you find the value of this expression, which contains infinitely nested square roots?

Small pepper seedlings in orange pots.
problem

A Third of the Area

Age
14 to 16
Challenge level
3 out of 3

The area of the small square is $\frac13$ of the area of the large square. What is $\frac xy$?