Grade 4 › G4U11 Time: Duration

Grade 4 › G4U11 Time: Duration › L3
GRADE 4 · ALBERTAOUTCOME AB-G4-4T1

L3 · Converting Hours, Minutes and Seconds

Learning goal

“I can convert between hours, minutes and seconds using the two facts 1 hour = 60 minutes and 1 minute = 60 seconds - multiplying to go to a smaller unit and grouping by 60 to go to a bigger unit.”

Convert — to rewrite the same amount in a different unit, like writing 120 minutes as 2 hours. The amount of time does not change; only its name tag changes.
Hour — a unit of time equal to 60 minutes.
Minute — a unit of time equal to 60 seconds. There are 60 minutes in one hour.
Second — the smallest of our three units. There are 60 seconds in one minute, so a second is a very short time - about one heartbeat.
Worked example

Change 3 hours into minutes, and 150 minutes into hours and minutes. Step 1: Hours are the BIG unit, minutes are the SMALL unit. Going big -> small, the number grows: multiply by 60. 3 hours = 3 x 60 = 180 minutes. Step 2: Going small -> big, group by 60. In 150 minutes: 150 / 60 makes 2 whole groups (120 minutes) with 30 minutes left over. Step 3: So 150 minutes = 2 hours 30 minutes. Timeline picture: three hour-blocks, each labelled "60 minutes," make a strip 180 minutes long; below it, a 150-minute strip fills two whole hour-blocks and half of the third. Say it plainly: the number 60 runs this whole lesson. Bigger unit -> smaller unit: multiply by 60. Smaller unit -> bigger unit: make groups of 60.

Check yourself — explain it

Why does 2 hours become a BIGGER number (120) when we write it in minutes?

Paired problem — example still visible

Change 4 hours into minutes. -> 240 minutes (4 x 60)

Faded completion — last step is yours

"125 minutes: two groups of 60 make 120 minutes, with 5 minutes left over. So 125 minutes = ___ hours ___ minutes." -> 2 hours 5 minutes

Ready to practise?

10 scored questions with a 3-rung hint ladder. Mastery needs 8/10 plus both gate questions.

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