Estimation Sequence Practice Test 2

In this series, each number is the sum of the two preceding numbers. For example, \(3 = 1 + 2\) and \(5 = 3 + 2\). Therefore, the number following 13 must be \(13 + 8 = 21\), and the next number must be \(21 + 13 = 34\).

In this series, the number subtracted from the preceding term increases by two for each term. For example, \(108 – 4 = 104\), \(104 – 6 = 98\), etc. For the next term, subtract 12 from 80 to get 68.

In this series, the number added to the preceding term increases by one for each term. For example, \(41 + 3 = 44\), \(44 + 4 = 48\), etc. For the next term, add 7 to 59 to get 66.

To estimate, round $4.05 to an even $4.00, then multiply by the number of people (15). The result is $60.

The series of numbers is formed by multiplying the previous number by a factor that increases by one each time. For example, \(4 \times 2 = 8\), \(8\times 3 = 24\), etc. So the next operation is to multiply 96 by 5, resulting in 480.

Each number is found by dividing the previous one by three:

• \(27 \div 3 = 9\)
• \(9\div 3 = 3\)
• \(3 \div 3 = 1\)

The next number in the series is \(1 \div 3 = \tfrac{1}{3}=0.333…\)

This is a geometric sequence where each number is multiplied by 3. For example, \(2 \times 3 = 6\) and \(6 \times 3 = 18\). So the next number is \(54 \times 3 = 162\).

The numbers decrease by 10, then 9, then 8, and so on.

For example, \(100 – 10 = 90\), \(90 – 9 = 81\), and \(81 – 8 = 73\).

The next difference is 7:

\(73 – 7 = 66\)

Round $1.49 to $1.50, then multiply:

\(7 \times 1.50 = 10.50\)

The best estimate is about $10.

Each term in the sequence is divided by 3. For example, \(81 \div 3 = 27\) and \(27 \div 3 = 9\). So the next number is \(3 \div 3 = 1\).