Triangular numbers
for 5th grade
Pick the missing number in these patterns of triangular numbers
Triangular numbers
In this topic you are asked to look at a series of numbers from the Triangular numbers series and fill in the missing number.
Triangular numbers are a sequence of numbers that can be arranged in the shape of a triangle. The first triangular number is 1, the second is 3, the third is 6, the fourth is 10, and so on.
To understand how these numbers work, imagine arranging objects in the shape of a triangle.
o
o o
o o o
o o o o
o o o o o
For example, if you arrange 3 objects, you can make a triangle with one object at the top and two objects on the next row. If you arrange 6 objects, you can make a triangle with one object at the top, two objects on the second row, and three objects on the third row.
The equation for working out the nth value in the series is Tn = 1 + 2 + 3 + ... + n
Triangular numbers show up in many places in math and science, from counting the number of dots in a triangular grid to understanding the properties of certain types of molecules.
Below is a table showing the first 6 question answer pairs for the topic "Triangular numbers" as used in the lessons for this topic. Our games and tests for the topic use these 6 items plus 11 additional question answer pairs.
The topic "Triangular numbers" is in the category Pattern for 5th grade (ages 10 to 11).
Revise 'Triangular numbers' with one of our games for 5th grade
Each of our math topics for elementary are made up of between 6 and 20 question and answer pairs (both the written form and a robot voice speaking those questions and answers). Each topic can be used with all the activities on the site.
Counting * Comparing numbers * Pattern * Place value * Addition * Subtraction * Add + Subtract * Multiplication * Division * Multiply + Divide * Fractions * Decimals * Ratio + proportion * Measurements * Shapes * Position + Direction * Statistics * Algebra *
