Arithmetic sequences

There are 50 NRICH Mathematical resources connected to Arithmetic sequences
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problem

Transformations Tables

Age
7 to 11
Challenge level
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These grids are filled according to some rules - can you complete them?
Red Balloons, Blue Balloons
problem

Red Balloons, Blue Balloons

Age
7 to 11
Challenge level
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Katie and Will have some balloons. Will's balloon burst at exactly the same size as Katie's at the beginning of a puff. How many puffs had Will done before his balloon burst?
Series Sums
problem

Series Sums

Age
14 to 16
Challenge level
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Let S1 = 1 , S2 = 2 + 3, S3 = 4 + 5 + 6 ,........ Calculate S17.
Prime AP
problem

Prime AP

Age
16 to 18
Challenge level
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What can you say about the common difference of an AP where every term is prime?
Natural Sum
problem

Natural Sum

Age
14 to 16
Challenge level
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The picture illustrates the sum 1 + 2 + 3 + 4 = (4 x 5)/2. Prove the general formula for the sum of the first n natural numbers and the formula for the sum of the cubes of the first n natural numbers.
Summats Clear
problem

Summats Clear

Age
16 to 18
Challenge level
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Find the sum, f(n), of the first n terms of the sequence: 0, 1, 1, 2, 2, 3, 3........p, p, p +1, p + 1,..... Prove that f(a + b) - f(a - b) = ab.
Days and Dates
problem

Days and Dates

Age
11 to 14
Challenge level
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Investigate how you can work out what day of the week your birthday will be on next year, and the year after...
Janusz asked
problem

Janusz asked

Age
16 to 18
Challenge level
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In y = ax +b when are a, -b/a, b in arithmetic progression. The polynomial y = ax^2 + bx + c has roots r1 and r2. Can a, r1, b, r2 and c be in arithmetic progression?
Be reasonable
problem

Be reasonable

Age
16 to 18
Challenge level
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Prove that sqrt2, sqrt3 and sqrt5 cannot be terms of ANY arithmetic progression.
Domino Sequences
problem

Domino Sequences

Age
5 to 7
Challenge level
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Find the next two dominoes in these sequences.