Clock Arithmetic and Modulo Operations

This video tutorial explains how to determine a previous time using mod 12 arithmetic, also known as clock arithmetic. It covers two examples: calculating the time 52 hours ago from 9:00 and 70 hours ago from 2:00. The tutorial demonstrates two methods for each example, verifying results using a clock. The video emphasizes understanding remainders and negative numbers in mod 12 calculations.

What is the main concept introduced in this lesson?

• Subtraction of time

• Addition of time

• Clock arithmetic or mod 12 arithmetic

• Multiplication of time

Tags

CCSS.4.NBT.B.6

In the first method for the first example, what is the remainder when 52 is divided by 12?

• 3

• 4

• 6

• 5

Tags

CCSS.3.MD.A.1

What time is it 52 hours before 9:00 using the first method?

• 6:00

• 5:00

• 7:00

• 4:00

Tags

CCSS.3.MD.A.1

In the second method for the first example, what is the result of -43 mod 12?

• 5

• 7

• 6

• 4

Tags

CCSS.3.MD.A.1

What time is it 52 hours before 9:00 using the second method?

• 6:00

• 7:00

• 5:00

• 4:00

Tags

CCSS.4.NBT.B.6

In the first method for the second example, what is the remainder when 70 is divided by 12?

• 11

• 8

• 9

• 10

Tags

CCSS.3.MD.A.1

What time is it 70 hours before 2:00 using the first method?

• 3:00

• 4:00

• 5:00

• 6:00

Tags

CCSS.3.MD.A.1

In the second method for the second example, what is the result of -68 mod 12?

• 5

• 4

• 3

• 6

Tags

CCSS.3.MD.A.1

What time is it 70 hours before 2:00 using the second method?

• 6:00

• 5:00

• 4:00

• 3:00

Tags

CCSS.3.MD.A.1

What is the key takeaway from the lesson on clock arithmetic?

• Understanding how to divide time

• Understanding how to multiply time

• Understanding how to use mod 12 arithmetic to find previous times

• Understanding how to add time