CK-12 Earth Science For High School covers the study of Earth - its minerals and energy resources, processes inside and on its surface, its past, water, weather and climate, the environment and human actions, and astronomy.

CK-12 Earth Science For Middle School covers the study of Earth - its minerals and energy resources, processes inside and on its surface, its past, water, weather and climate, the environment and human actions, and astronomy.

This short video and interactive assessment activity is designed to teach third graders about beginning, ending, and elapsed time with clocks - word problems.

This short video and interactive assessment activity is designed to teach second graders about beginning, ending, and elapsed time with clocks - word problems.

This short video and interactive assessment activity is designed to teach fourth graders about beginning, ending, and elapsed time with clocks - word problems.

This short video and interactive assessment activity is designed to teach second graders about solving for start time, end time, or elapsed time.

This short video and interactive assessment activity is designed to teach fifth graders about elapsed time - finding the starting time (single step).

This short video and interactive assessment activity is designed to teach fourth graders about finding the time with a timeline.

This site is a series of video lectures and interactive exercises for teaching basic mathematics skills to first graders. It has separate addition and subtraction skills reviews numbers up to 10, 20, and 100; a section on telling time and reading clocks as well as course material on measurement and geometry.

Ck-12's Grade 2 Elementary Math is a series of videos and interactive videos designed to teach basic math concepts to 2nd graders. Concepts covered include Addition and Subtraction, Multiplication, Place Value, Decimals, Time, Fractions, Money, Measurement, and Geometry.

CK-12's Elementary Math Grade 3 is a series of videos and interactive videos designed to teach basic math concepts to 3rd graders. Concepts covered include Addition and Subtraction, Multiplication, Division, Place Value, Decimals, Time, Factors and Multiples, Money, Measurement, and Geometry.

CK-12's Grade 4 Elementary Math is a series of videos and interactive videos designed to teach basic math concepts to 4th graders. Concepts covered include Addition and Subtraction, Multiplication and Division, Multiple Operations and Grouping, Place Value, Decimals, Time, Money, Measurement, and Geometry.

CK-12's Grade 5 Elementary Math is a series of videos and interactive videos designed to teach basic math concepts to 5th graders. Concepts covered include Multiplication and Division, Place Value, Multiple Operations and Grouping, Decimals, Time, Fractions, Money, Measurement, and Geometry.

Introduces engineering techniques and practices to high school students. The nature of engineering and it's societal impact are covered, as well as the educational and legal requirements needed to become an engineer. This book is designed for a broad range of student abilities and does not require significant math or science prerequisites.

This short video and interactive assessment activity is designed to teach second graders an overview - equivalent decimals ending in zero.

This short video and interactive assessment activity is designed to teach third graders an overview - thousandths.

This short video and interactive assessment activity is designed to give fourth graders an overview of - equivalent decimals ending in zero.

This short video and interactive assessment activity is designed to teach fourth graders about estimating measure by image: centimeters or meters?.

This short video and interactive assessment activity is designed to teach fifth graders about estimating the measure of objects by image: feet or inches?.

This short video and interactive assessment activity is designed to teach fourth graders about estimating measure by description - multiple choice.