Increasing or Decreasing by a Fraction of a Quantity

Visual models support young mathematicians as they deepen their fractional number sense in this elementary math instructional activity. Using fraction circle manipulatives, children explore basic unit fractions as they develop...

Visual models support young mathematicians with exploring equivalent fractions. Starting with a quick warm-up problem, children go on to work through a series of guiding practice problems before working with a partner identifying and...

Explore the effect sample size has on margin of error and confidence interval. The instructor calculates the margin of error of fictional data. He shows how the calculation changes when the sample size changes while keeping the other...

Ramp up the average rate of change—instantly. Learners use their knowledge of the formula to find the average rate of change to find the instantaneous rate of change. The presenter shows pupils an interactive that demonstrates finding...

This video on changing improper fractions to mixed numbers would nicely complement the Khan Academy video on writing mixed numbers as improper fractions. Sal first shows students how to convert improper fractions. Then, he uses drawings...

Sal adds a few more steps to these problems as he solves algebraic equations with two steps, though he states that "there's more than one way to do it." Those who become confused by increasingly complicated algebra problems on a test...

Your car decreases in value from $20,000 to $17,000. What percent of the value have you lost? Pupils answer word problems by determining the percent of change. 

The instructor uses a graph representing time and distance to illustrate how to solve this word problem. She explains each step: rate of change, distance, time, vertical change over horizontal change, change in distance, and change in...

This dreamy resource has little ones computing the change on the purchase of an ice cream cone. Mia describes each step in two methods: subtraction of decimals and counting up from the sale price.

How much did it change? The presenter works two problems to demonstrate how to calculate percentage loss and increase. Pupils have one learning exercise to practice similar problems on their own.