# 5-Sep-14Created by Mr.Lafferty Maths Dept Time Converting 12hour to 24 hour clock Counting Method www.mathsrevision.com Adding / Subtracting Time Level.

## Presentation on theme: "5-Sep-14Created by Mr.Lafferty Maths Dept Time Converting 12hour to 24 hour clock Counting Method www.mathsrevision.com Adding / Subtracting Time Level."— Presentation transcript:

5-Sep-14Created by Mr.Lafferty Maths Dept Time Converting 12hour to 24 hour clock Counting Method www.mathsrevision.com Adding / Subtracting Time Level D

5-Sep-14Created by Mr.Lafferty Maths Dept Starter Questions www.mathsrevision.com Level D Q1.Calculate Q2.Round to 1 decimal place 2.354 Q3. How many minutes in 1 hour Q4.The answer to the question is 10. What is the question.

5-Sep-14Created by Mr.Lafferty Maths Dept www.mathsrevision.com Learning Intention Success Criteria 2.Change from 24 to 12 hour clock. 1.To explain how to convert between 12 and 24 hour clock and vice versa. Revision Level D 1.Change from 12 to 24 hour clock. Converting Time Level D

5-Sep-14Created by Mr.Lafferty Maths Dept 230022002100200019001800170016001500140013001200 11 pm10 pm9 pm8 pm7 pm6 pm5 pm4 pm3 pm2 pm1 pmmidday 110010000900080007000600050004000300020001000000 11 am10 am9 am8 am7 am6 am5am4 am3 am2 am1 am midnight 12Hour to 24 Hour Clock To go from 12 hour clock to 24 hour clock just add 12 to the pm hours: 2000 2100 1830 2330 1620 Examples 8 pm becomes 9 pm becomes 6:30 pm becomes 11:30 pm becomes 4:20 pm becomes 3:10 pm becomes 1510

5-Sep-14Created by Mr.Lafferty Maths Dept 230022002100200019001800170016001500140013001200 11 pm10 pm9 pm8 pm7 pm6 pm5 pm4 pm3 pm2 pm1 pmmidday 110010000900080007000600050004000300020001000000 11 am10 am9 am8 am7 am6 am5am4 am3 am2 am1 am midnight 24 Hour to 12 Hour Clock To go from 24 hour clock to 12 hour clock just subtract 12 from the hours if it is greater than 12: 8 pm 9 pm 5:30 pm 10:08 pm 8:06 pm Examples 2000 becomes 2100 becomes 1730 becomes 2208 becomes 2006 becomes 1350 becomes 1:50 pm

greater than 12 subtract 12 Let’s make up our own questions ! 5-Sep-14Created by Mr.Lafferty Maths Dept www.mathsrevision.com Level D Converting Time Key Points 12 hour clock Analogue clock ALWAYS use AM or PM 24 hour clock Digital clock NEVER use AM or PM pm times add on 12 ALWAYS 4 digits Hours 0 - 24 Hours 1 - 12

5-Sep-14Created by Mr.Lafferty Maths Dept Now try Exercise 1 Ch4 (page 45) www.mathsrevision.com Time Level D

5-Sep-14Created by Mr.Lafferty Maths Dept Starter Questions Starter Questions www.mathsrevision.com Level D P Q R

5-Sep-14Created by Mr.Lafferty Maths Dept www.mathsrevision.com Learning Intention Success Criteria 2.Find time differences between two times, showing all working. 1.To explain the counting method to find the difference between two times. 1.Understand the counting method. Counting Method Level D

5-Sep-14Created by Mr.Lafferty Maths Dept www.mathsrevision.com Level D Counting Method When working out time difference we will use the Counting Method. This method will always work. Example : Find the time difference between 08 40 hrs and 11 10 hrs 08 4011 0011 10 HrsMins 20 2 10 230 nearest hour What’s left + 09 00 hours 20 mins2 hrs10 mins

A bus leaves Kirkintilloch Main Street at 14 40 hrs and arrives in Aberdeen at 18 50 hrs. How long was the journey. 5-Sep-14Created by Mr.Lafferty Maths Dept www.mathsrevision.com Level D Counting Method 14 4018 0018 50 HrsMins 20 3 50 370 nearest hour What’s left + 15 00 hours 20 mins3 hrs50 mins But there are 60 minutes = 1hour 70 mins = 1hr 10mins 4hrs 10 mins

Using Timetables 2314 2302 2254 2248 2243 2237 2225 2214 2202 2154 2148 2143 2137 2125 2114 2102 2054 2048 2043 2037 2025 Until Hour Every And 1114 1102 1054 1048 1043 1037 1025 1014 1002 0954 0948 0943 0937 0925 0914 0902 0854 0848 0843 0837 0825 Glasgow Bus Station George Square Port Dundas Springburn Milton Bishopbriggs Kirkie Bus Station * * * How long does the first bus take from Kirkie to Glasgow. 35 0 14 HrsMins 49 + 08 2509 0009 14 nearest hour What’s left 09 00 hours 35 mins0 hrs14 mins 35 0 14

Let’s make up our own question ! The key steps are left on the slide to help you. 5-Sep-14Created by Mr.Lafferty Maths Dept www.mathsrevision.com Level D Counting Method HrsMins nearest hour What’s left + hours mins hrs mins But there are 60 minutes = 1hour

5-Sep-14Created by Mr.Lafferty Maths Dept Now try Exercise 2 Ch4 (page 47) www.mathsrevision.com Level D Counting Method

5-Sep-14Created by Mr.Lafferty Maths Dept Starter Questions Starter Questions www.mathsrevision.com Level D

5-Sep-14Created by Mr.Lafferty Maths Dept www.mathsrevision.com Learning Intention Success Criteria 1.To explain how round to the nearest second and also add and subtract minutes and seconds. 1.Round to the nearest second. Time Minutes and Secs Level D 2.Add and subtract minutes and seconds.

5-Sep-14Created by Mr.Lafferty Maths Dept www.mathsrevision.com Time Minute & Seconds Level D Rounding time to 1 or 2 decimal places is just the same as rounding any number. Example : Round the times to 1 and 2 decimals places (a)4.573 secs 4.6 secs to 1 decimal place 4.57 secs to 2 decimal place (b)52.455 secs 52.5 secs to 1 decimal place 52.46 secs to 2 decimal place

To add and subtract time we must remember 5-Sep-14Created by Mr.Lafferty Maths Dept www.mathsrevision.com Level D Adding & Subtracting Time MinsSecs + 60 secs = 1min (a) Add 4 mins 30secs to 2 mins 25 mins Always layout in columns 430 225 655

To add and subtract time we must remember 5-Sep-14Created by Mr.Lafferty Maths Dept www.mathsrevision.com Level D Adding & Subtracting Time MinsSecs + 60 secs = 1min (a) Add 3 mins 35 secs to 9 mins 45 mins Always layout in columns 335 945 12 80 80 secs =1min 20 secs =13min 20 secs

To add and subtract time we must remember 5-Sep-14Created by Mr.Lafferty Maths Dept www.mathsrevision.com Level D Adding & Subtracting Time MinsSecs - 60 secs = 1min (a) Subtract 2 mins 35secs from 5 mins 40 mins Always layout in columns 540 235 305 3 1

To add and subtract time we must remember 5-Sep-14Created by Mr.Lafferty Maths Dept www.mathsrevision.com Level D Adding & Subtracting Time MinsSecs - 60 secs = 1min (a) Subtract 3 mins 30secs from 7 mins 20 mins Always layout in columns 720 330 350 60 6

5-Sep-14Created by Mr.Lafferty Maths Dept Now try Exercise 3 Ch4 (page 49) www.mathsrevision.com Time Minute & Seconds Level D

Similar presentations