This lesson covers the concept that when given two equations in the same format, those equations can be added or subtracted.

This short video and interactive assessment activity is designed to teach third graders about one step addition and subtraction - word problems.

This short video and interactive assessment activity is designed to teach fourth graders about one step metric capacity with addition and subtraction - word problems.

This short video and interactive assessment activity is designed to teach fifth graders about addition in kilograms.

This short video and interactive assessment activity is designed to teach fourth graders about addition of capacities - word problems.

This short video and interactive assessment activity is designed to teach fifth graders about addition of compound unit capacities - word problems.

In this lesson, students understand addition of integers as putting together or counting up, where counting up a negative number of times is counting down. Students use arrows to show the sum of two integers, p + q, on a number line and to show that the sum is distance | q | from p to the right if q is positive and to the left if q is negative. Students refer back to the Integer Game to reinforce their understanding of addition.

This short video and interactive assessment activity is designed to teach third graders about addition of sequential capacities - word problems.

This lesson and resource helps students strengthen their persuasive writing by identifying and responding to counterarguments.

As emissions of heat-trapping bases accumulate in our atmosphere, Earth's polar regions are warming more quickly than at lower latitudes. The rapid environmental changes that result from this warming can have a significant impact on the physical and mental health of rural Alaskans: unpredictable weather and changes in the seasons have made harvesting food more difficult, hazardous, and stressful. The risk of physical injury has also increased, as poor ice, extreme weather, and coastal erosion bring new travel hazards. Increasingly difficult harvest conditions for fish, shellfish, berries, caribou, and sea mammals have also increased concerns about food security. Additionally, declines in snow pack, the threat of drought, changes in lake and river conditions, and damage and disruptions to community water systems have prompted concerns of water security. The climate-related challenge faced by Alaska’s tribal health system is to recognize new health stressors and community vulnerabilities, and then find healthy adaptation strategies in an increasingly uncertain future.

In 2012, water managers in Fredericktown, Missouri, saw their city's main source of water dwindle. They used the EPA’s Climate Ready Water Utilities program to consider options and develop plans to protect their water source.

This page contains a transcript of President Harry S. Truman's address before Congress seeking $400 million in military and economic assistance for Turkey and Greece.

This page contains a transcript of a speech by President John F. Kennedy regarding the installation of Soviet missiles in Cuba.

Students choose a phrasal verb from a word bank to complete the sentences.

Students will read a cloze passage and select prepositions from a word bank to complete the story.

This course features a video review of addition up to the sum of ten for first graders.

This short video and interactive assessment activity is designed to teach second graders an overview of addition (sums to 10).

This short video and interactive assessment activity is designed to teach second graders an overview of addition.