Uncover what happened earlier
Find missing starting amounts, changes and original shares.
Explore this lesson →5 practice questions · Optional read aloud · Thinking pad
Let’s understand the idea.
- Read the whole story and the final question. The amount you need may be at the start, in the middle or at the end.
- Choose your own way to organize the quantities. You can draw, write several equations or reason mentally. The thinking pad is available if you want it.
- Let n name the requested number. Keep each useful amount labeled so you answer the question that was actually asked.
- Check your answer in the original situation. Reversing a change or combining the parts can help you check it.
- After your attempt, compare your method with a worked route. More than one valid route may lead to the same answer.
Something to notice
These fresh stories omit supplied intermediate targets and equation options. The API checks the requested numerical answer and shows a labeled worked route afterward. It does not automatically assess a self-created sketch, equation sequence or oral explanation; observe those separately. First-try correctness here is evidence for these items, not retention, full modeling competence or mastery of 4.OA.A.3. Contextual remainder and estimation work is separate.
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 4 · 4.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.