Place value

This 100 square jigsaw is written in code. It starts with 1 and ends with 100. Can you build it up?

You have a set of the digits from 0 to 9. Can you arrange these in the five boxes to make two-digit numbers as close to the targets as possible?

You have two sets of the digits 0-9. Can you arrange these in the five boxes to make four-digit numbers as close to the target numbers as possible?

Using balancing scales what is the least number of weights needed to weigh all integer masses from 1 to 1000? Placing some of the weights in the same pan as the object how many are needed?

Can you find the chosen number from the grid using the clues?

Four of these clues are needed to find the chosen number on this grid and four are true but do nothing to help in finding the number. Can you sort out the clues and find the number?

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.

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

Weekly Problem 48 - 2013
What is the remainder when the number 743589×301647 is divided by 5?

In this 100 square, look at the green square which contains the numbers 2, 3, 12 and 13. What is the sum of the numbers that are diagonally opposite each other? What do you notice?