Three groups, one total
Solve stories that join three groups, with totals up to twenty.
Explore this lesson →5 practice questions · Optional read aloud · Thinking pad
Let’s understand the idea.
- Find all three groups in the story. Count each object in just one group.
- Join two groups, then add the third. Look for an easy pair, such as two parts that make ten.
- Check that your total includes every group exactly once.
Something to notice
Ask the learner to retell a fresh story, identify the unknown amount and explain why their picture or equation fits. A correct numeric answer alone does not establish reading comprehension or mastery of the whole standard.
Try it. Change it. Explain it.
Open the lesson to use its pictures and controls. In How it works, connect the picture to the idea. In Play & discover, change the quantities and notice what stays the same. In Your turn, answer questions and use the explanation to check your reasoning.
You can ask for help, draw on the thinking pad, or listen to the question and answer options. Progress distinguishes independent work from work completed with help.
Let’s try it →Curriculum connection
Grade 1 · 1.OA · US Common Core
This lesson is mapped to these standards. A completed activity is practice evidence, not a claim of mastery. Content is checked against the linked official standards and its mathematical models are tested.