Delaware Grade 3 Math

Work through the example

An afternoon reading session begins at 2:35 and ends at 3:20. How many minutes does it last? Use the next whole hour as a helpful stopping point.

Connect the model and calculation

From 2:35 to 3:00 is 25 minutes, because 60 − 35 = 25. From 3:00 to 3:20 is another 20 minutes. Add the two intervals: 25 + 20 = 45 minutes. The session lasts 45 minutes. A check starts at 2:35, moves forward 25 minutes to 3:00, then another 20 to 3:20. Both parts must connect without a gap or overlap.

Understand an incorrect answer

Subtracting 35 from 20 without accounting for the hour change does not measure the interval. A clock hour has 60 minutes, so its written times cannot be handled like ordinary decimal numbers. Another error is to call 2:35 to 3:00 thirty-five minutes; that is the number of minutes already past two, not the minutes remaining before three. Draw or point to the remaining part of the hour.

Transfer the idea to another example

Keep the start at 2:35 and move the end to 3:10. The intervals become 25 and 10 minutes, totaling 35. Then ask what end time would follow a 30-minute session starting at 2:35: 25 minutes reaches 3:00 and five more reaches 3:05. Have the student label each jump with a duration and each endpoint with a clock time. That distinction helps when moving between an elapsed-time question and a missing-end-time question.

Selected Delaware Grade 3 references

The Delaware mathematics standards directory links the Common Core publisher. Delaware’s standards regulation, section 1.1.1.1, identifies adoption for the 2010–11 school year. Use the adopted document alongside the school’s instructional plan. These labels summarize the activity’s focus; read the complete expectations and mathematical practices in the publisher’s mathematics document.

Sources checked October 5, 2026. This selected activity is an entry point for instruction, not a complete curriculum checklist.

Connect the explanation with practice

Use the lesson, worksheet, and quiz directory to choose a related skill. The existing resource links remain available; open each activity’s directions to understand its timer, tools, question count, and scoring.

Grade 3 is within Delaware’s Smarter Balanced mathematics testing range. The linked learning resources have their own directions and scoring; a practice score does not establish an official state performance level. Read Delaware’s official summative assessment overview.

Keep one example of the student’s reasoning with the practice result. Choose a smaller model, a related question, or a new context according to the difficulty revealed in the worked activity.