Place value

problem

So Many Sums

Age

11 to 14

Challenge level

2 out of 3

In this addition each letter stands for a different digit, with S standing for 3. What is the value of YxO?
problem

Kangaroo Subtraction

Age

11 to 14

Challenge level

2 out of 3

Can you solve this 'KANGAROO' alphanumeric subtraction?
problem

Halfway

Age

11 to 14

Challenge level

2 out of 3

Can you find a number that is halfway between two fractions?
problem

Double With 1 to 9

Age

11 to 14

Challenge level

2 out of 3

Can you find a number and its double using the digits $1$ to $9$ only once each?
problem

Football Sum

Age

11 to 14

Challenge level

2 out of 3

Find the values of the nine letters in the sum: FOOT + BALL = GAME
problem

Seven Up

Age

11 to 14

Challenge level

3 out of 3

The number 27 is special because it is three times the sum of its digits 27 = 3 (2 + 7). Find some two digit numbers that are SEVEN times the sum of their digits (seven-up numbers)?
problem

Quick Times

Age

11 to 14

Challenge level

3 out of 3

Can you verify and generalise these equations?
problem

Basically

Age

11 to 14

Challenge level

3 out of 3

The number 3723 (in base 10) is written as 123 in another base. What is that base?
problem

Please Explain

Age

11 to 14

Challenge level

3 out of 3

Visitors to Earth from the distant planet of Zub-Zorna were amazed when they found out that when the digits in this multiplication were reversed, the answer was the same! Find a way to explain why this works.
problem

Back to the Planet of Vuvv

Age

11 to 14

Challenge level

3 out of 3

There are two forms of counting on Vuvv - Zios count in base 3 and Zepts count in base 7. Can you work out in which direction the Zios and Zepts were looking, based on the information you're given?