# 3.9 - Time

The student will

a)   tell time to the nearest minute, using analog and digital clocks;

b)   solve practical problems related to elapsed time in one-hour increments within a 12-hour period; and

c)   identify equivalent periods of time and solve practical problems related to equivalent periods of time.

### BIG IDEAS

• So that I can get to events on time

• So that I know when an event will start or when it will end

• So that I understand that the 12-hour cycle continues and repeats

### UNDERSTANDING THE STANDARD

• Students need to understand that time has passed or will pass in equal increments (i.e., seconds, minutes, or hours).
• The use of an analog clock facilitates the understanding of time relationships between minutes and hours and hours and days.
• Students need to understand that there are sixty minutes in an hour when using analog and digital clocks.
• Use of a demonstration clock with gears ensures that the positions of the hour hand and the minute hand are precise when time is read.
• Elapsed time is the amount of time that has passed between two given times.
• Elapsed time should be modeled and demonstrated using geared analog clocks and timelines
• Elapsed time can be found by counting on from the beginning time or counting back from the ending time.
• The use of a calendar facilitates the understanding of time relationships between days and months, days and weeks, days and years, and months and years.  Students need to know the relationship between periods of time (e.g., If there are 24 hours in one day, how many hours are in three days?).
• The knowledge that a year has about 365 1/4 days will help students understand the necessity of adding a full day every fourth year, called a leap year

### ESSENTIALS

The student will use problem solving, mathematical communication, mathematical reasoning, connections, and representations to

• Tell time to the nearest minute, using analog and digital clocks. (a)
• Match a written time (e.g., 4:38, 7:09, 12:51) to the time shown on analog and digital clocks to the nearest minute. (a)

• Solve practical problems related to elapsed time in one-hour increments, within a 12-hour period (within a.m. or within p.m.):

• when given the beginning time and the ending time, determine the time that has elapsed; (b)
• when given the beginning time and amount of elapsed time in one-hour increments, determine the ending time; or (b)
• when given the ending time and the elapsed time in one-hour increments, determine the beginning time. (b)
• Identify the number of minutes in an hour and the number of hours in a day. (c)

• Identify equivalent relationships observed in a calendar, including the approximate number of days in a given month (about 30), the number of days in a week, the number of days in a year (about 365 ), and the number of months in a year. (c)

• Solve practical problems related to equivalent periods of time to include:

• approximate days in five or fewer months;
• days in five or fewer weeks;
• months in five or fewer years;
• minutes in five or fewer hours; and
• hours in five or fewer days. (c)

### KEY VOCABULARY

Updated: Aug 22, 2018