There are **9** NRICH Mathematical resources connected to **Rounding**, you may find related items under The Number System and Place Value.

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Four strategy dice games to consolidate pupils' understanding of rounding.

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Use two dice to generate two numbers with one decimal place. What happens when you round these numbers to the nearest whole number?

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What happens when you round these three-digit numbers to the nearest 100?

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What happens when you round these numbers to the nearest whole number?

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This activity involves rounding four-digit numbers to the nearest thousand.

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

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The problem is how did Archimedes calculate the lengths of the sides of the polygons which needed him to be able to calculate square roots?

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A sequence of numbers x1, x2, x3, ... starts with x1 = 2, and, if you know any term xn, you can find the next term xn+1 using the formula: xn+1 = (xn + 3/xn)/2 . Calculate the first six terms of this sequence. What do you notice? Calculate a few more terms and find the squares of the terms. Can you prove that the special property you notice about this sequence will apply to all the later terms of the sequence? Write down a formula to give an approximation to the cube root of a number and test it for the cube root of 3 and the cube root of 8. How many terms of the sequence do you have to take before you get the cube root of 8 correct to as many decimal places as your calculator will give? What happens when you try this method for fourth roots or fifth roots etc.?