G10 Arithmetic Series

The sum of the first n terms of an arithmetic sequence can be negative.

• True
• False

Reorder the following numbers so they form an arithmetic sequence with a common difference of -4:

• -1

• 7

• 11

• 3

• -5

Which of the following arithmetic sequences has a sum of 560?

• 92, 102, 112, 122, 132

• 108, 110, 112, 114, 116

• 118, 115, 112, 109, 106

• 95, 99, 103, 107, 111

What is the sum of the counting numbers from 1 to 79?

Mathematical Equivalence

ON

The first term of an arithmetic sequence is 3, and the sum of the first 15 terms is 255. What is the common difference?

Mathematical Equivalence

ON

A farmer plants 15 trees in the first row, 18 in the second row, 21 in the third row, and so on, until there are 25 rows. How many trees are there in the 17th row and in total?

• 1275

• n for total=

• 15

• S₂₅ =

• 25

• a₁ =

• 63

• a₂ =

• 18

• a₁₇ =

Solve 5 + (–1) + (–7) + … + (–55)

Mathematical Equivalence

ON

The sum of the first n terms of an arithmetic sequence can be found using the formula:

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