A polite number can be written as the sum of two or more consecutive positive integers. Find the consecutive sums giving the polite numbers 544 and 424. What characterizes impolite numbers?
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. . . .
What can you say about the common difference of an AP where every term is prime?
Use this interactivity to sort out the steps of the proof of the formula for the sum of an arithmetic series. The 'thermometer' will tell you how you are doing
Here is a machine with four coloured lights. Can you make two lights switch on at once? Three lights? All four lights?
Prove that sqrt2, sqrt3 and sqrt5 cannot be terms of ANY arithmetic progression.
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.
This group tasks allows you to search for arithmetic progressions in the prime numbers. How many of the challenges will you discover for yourself?
Watch the video to see how to add together an arithmetic sequence of numbers efficiently.
Watch the video to see how Charlie works out the sum. Can you adapt his method?
A story for students about adding powers of integers - with a festive twist.
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?
Let S1 = 1 , S2 = 2 + 3, S3 = 4 + 5 + 6 ,........ Calculate S17.
Cellular is an animation that helps you make geometric sequences composed of square cells.
Here is a machine with four coloured lights. Can you develop a strategy to work out the rules controlling each light?