Digital/ Analog Time 4th Strategies for Your Toolbox in Solving Problems Involving Digital/ Analog Time

Vocabulary Digital clock: instrument that reads time in a numerical format Analog clock: time represented by hands on a dial

Digital Clocks When reading a digital clock, 5 hours and 8 minutes the 1st number to the left of the colon is the hour the 2nd number to the right of the colon is the minutes 2nd number 1st number 5 hours and 8 minutes

Analog Clocks Reading an analog clock: short hand represents the hour long hand represents minutes hour = short word = short hand minutes = long word = long hand count by 5s to find total minutes if minute hand is on a number 1-12, otherwise count by 1s

Counting by 5s 60 5 55 10 50 45 15 40 20 25 35 30

Toolbox Strategies for Reading/ Matching Digital & Analog Time 1st number on a digital clock always matches number the short hand is on if the short hand is between 2 numbers, the hour is the lesser of the 2 numbers Count Us In Games - Game 10 Aplusmath.com : Flashcards : Analog Clocks

Elapsed Time Elapsed time – time that has passed Ex: If I say that the party lasted from 5:30 PM to 7:30 PM, then 2 hours passed, or elapsed. It can be measured in: seconds minutes hours days weeks Picturing or using a clock will help

Types of Elapsed Time Problems 1. You know when an event started and when it ended. You have to find the amount of time that has passed. Ex: The TV program started at 8:30 PM and ended at 9:00 PM. How many minutes did the program last?

Types of Elapsed Time Problems Ex: The TV program started at 6:30 PM & ended at 7:00 PM. How many minutes did the program last? To calculate the total minutes Picture a clock showing 6:30 Count by 5s until you reach 7:00

Types of Elapsed Time Problems Ex: The TV program started at 6:30 PM & ended at 7:00 PM. How many minutes did the program last? To calculate the total minutes Picture a clock showing 6:30 Count by 5s until you reach 7:00 Before revealing “Notice that the clock…” ask students to read what time does the clock say. * Notice that the clock now shows 7:00

Types of Elapsed Time Problems Ex: The TV program started at 6:30 PM & ended at 7:00 PM. How many minutes did the program last? To calculate the total minutes (strategy 2) Since the question asks about minutes, subtract them (30 min – 00 min = 30 min) - Answer: 30 minutes

Types of Elapsed Time Problems 2. You know when an event started and how long it will last. You have to find when the event will end. Ex: The TV program started at 1:30 PM and lasted for 30 minutes. When did the program end?

Types of Elapsed Time Problems Ex: The TV program started at 1:30 PM and lasted for 30 minutes. When did the program end? To calculate the program end time You’re told how long the program lasted in minutes. Add the minutes from the start time to the minutes of how long the program lasted. (30 min + 30 min = 60 min)

Types of Elapsed Time Problems Ex: The TV program started at 1:30 PM and lasted for 30 minutes. When did the program end? To calculate the program end time When working with units of measurement, it’s best to use easy numbers so whenever possible convert to a unit that reduces a bigger number. 60 minutes is equal to 1 hour so add the hours: 1hour from the start time to 1 hour from the minutes added together (1 hr + 1 hr = 2 hrs) Answer: 2:00 PM

Types of Elapsed Time Problems You know when the even will end, and how long it will last so you have to find when the event will begin. Ex: The TV program lasted for 30 minutes and ended at 2:00. When did the program start?

Types of Elapsed Time Problems Ex: The TV program lasted for 30 minutes and ended at 2:00 PM. When did the program start? To calculate the start time There are 2 hours to work with since the program ended at 2:00. 60 minutes equal 1 hour, so subtract 30 minutes from 60 minutes (60 min – 30 min = 30 min) The time that’s left is 1 hour and 30 minutes Answer: 1:30 PM

Let’s practice some elapsed time problem!! mathFROG - Fun Resources & Online Games

Elapsed Time Practice 15 minutes How much time has gone by between the times on the first and second clocks? 15 minutes 15 minutes

Elapsed Time Practice How much time has gone by between the times on the first and second clocks? 55 minutes 55 minutes

Elapsed Time Practice Maureen started her homework at 7.20 p.m. She finished it at 8.05 p.m. How long did she take to do her homework? 50 minutes

Toolbox Checklist for Solving Elapsed Time Problems Analog clock (You can make, draw, or use one that your teacher may provide.) Knowledge to remember: hour hand = short word = short hand; minute hand = long word = long hand Manipulate the hands to show times Knowledge to remember: 60 seconds = 1 minute; 60 minutes = 1 hour Count by 5s

Questions???