3.7.C
The Standard
determine the solutions to problems involving addition and subtraction of time intervals in minutes using pictorial models or tools such as a 15-minute event plus a 30-minute event equals 45 minutes
Texas Essential Knowledge and Skills for Mathematics
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students add or subtract lengths of time measured in minutes. They use clock faces, number lines, or drawings to solve and explain elapsed-time situations.
What Mastery Looks Like
- Students find an unknown duration accurately and label the answer in minutes. They use a clock, number line, or drawing to show how the intervals were combined or separated.
Common Misconceptions
- Students may treat minutes like base-ten numbers and write 75 minutes as 0:75. They may also subtract the start time from the end time incorrectly when an interval crosses an hour.
How to Assess It
- Give an exit ticket: “Art lasts 25 minutes and music lasts 35 minutes. How long do both classes last? Show your thinking with a number line or clock.”
Lesson moves
Ways to Teach It
Give pairs clock faces and event cards, then have them move the hands to combine two event lengths.
Ask students to write how they would find the total time for a 20-minute lunch and a 35-minute recess.
Play Time Interval Match by pairing story cards with answer cards and open number line models.
Use a class schedule to find the combined length of two activities or the difference between their durations.
Keep exploring
Related Standards
- 4.3.E
represent and solve addition and subtraction of fractions with equal denominators using objects and pictorial models that build to the number line and propertie...
- 2.10.C
write and solve one-step word problems involving addition or subtraction using data represented within pictographs and bar graphs with intervals of one
- 1.5.D
represent word problems involving addition and subtraction of whole numbers up to 20 using concrete and pictorial models and number sentences
- 3.5.A
represent one- and two-step problems involving addition and subtraction of whole numbers to 1,000 using pictorial models, number lines, and equations
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