# Videos Solve Problems and Compare Situations
In this video, Marta learns how to compare groups of items, without counting them, to determine which group has more. The End of Trotsky and the Rise of Stalin
Watch this video and find information about the Russian Revolution, Trotsky's fall from power, and the rise of Stalinist Russia. Using Inverse in Multiplication and Division
This video shows students the inverse relationship between multiplication and division. They will also learn to use the inverse to check their… Zebra and Spider: Sense of Touch
Find information and a video about an unlikely pair, zebra and spider, two animals that share a heightened sense of touch. 2 and 5 as Factors
In this video, Carlos learns about patterns in the multiplication of 2 and 5. Calculating the Volume of a Sphere
This video will show students how to find the formula to calculate volume for a sphere. Describing Accuracy with Percent Error
This video demonstrates how to solve a percent error by analyzing the estimated value and actual value. Estimate Decimal Quotients
In this video, Alex learns how to estimate a division problem when both numbers are decimals. Finding the Product of Two Mixed Numbers
This video teaches students to multiply two mixed numbers by changing them to improper fractions, then how to multiply and simplify. Grammar Song: Punctuation
This grammar song explains the purpose of punctuation when writing statements, commands, questions, and exclamations.