Understanding Percentages and Relationships

This video tutorial covers the concept of percent increase and decrease, using diagrams and equations to illustrate these changes. It includes exercises on expressing percent changes as percentages of initial amounts, graphing relationships in circles, and solving equations related to flour purchases. The tutorial also provides guidance on finding illustrative math lessons.

In the first diagram, if y is three out of four sections of x, what is the percentage decrease of y relative to x?

• 25% decrease

• 25% increase

• 50% decrease

• 75% increase

In the second diagram, if y is five sections and x is four sections, what is the percentage increase of y relative to x?

• 30% increase

• 10% increase

• 20% increase

• 25% increase

If a bakery used 40% more flour this month compared to last month, what percentage of last month's flour does this month's usage represent?

• 160%

• 140%

• 120%

• 100%

If the bakery used 75% less milk this month compared to last month, what percentage of last month's milk does this month's usage represent?

• 75%

• 100%

• 50%

• 25%

If there was 40% more snow this year than last year, what percentage of last year's snow does this year's snow represent?

• 140%

• 160%

• 120%

• 100%

If there were 25% fewer sunny days this year than last year, what percentage of last year's sunny days does this year's represent?

• 50%

• 75%

• 100%

• 125%

What is the relationship between the diameter and circumference of a circle?

• Diameter is twice the circumference

• Circumference is twice the diameter

• Circumference is pi times the diameter

• Diameter is pi times the circumference

If Priya bought x grams of flour and Claire bought 3/8 more than Priya, which equation represents the amount Claire bought?

• y = x + 3/8

• y = 3/8x

• y = x - 3/8x

• y = x + 3/8x

If Claire bought 3/8 more flour than Priya, what is the equivalent expression for the total amount Claire bought?

• 5/8x

• 8/8x

• 11/8x

• 3/8x

How can you quickly find illustrative math lessons using a search?

• Search by topic name

• Search by teacher's name

• Search by hashtag with grade, unit, and lesson number

• Search by school name