Place value

Replace each letter with a digit to make this addition correct.

Can you substitute numbers for the letters in these sums?

Can you arrange the digits 1,2,3,4,5,6,7,8,9 into three 3-digit numbers such that their total is close to 1500?

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

Investigate the different ways these aliens count in this challenge. You could start by thinking about how each of them would write our number 7.

Can you solve this 'KANGAROO' alphanumeric subtraction?

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

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

When the number x 1 x x x is multiplied by 417 this gives the answer 9 x x x 0 5 7. Find the missing digits, each of which is represented by an "x" .

Find b where 3723(base 10) = 123(base b).