Grade 4 Maths Resources (7.1 Time - 12-hour & 24-hour Clock ... - Free Printable

Problem Overview:

The task involves filling in a table that converts times between the 12-hour clock and the 24-hour clock formats. The table includes times expressed in words, as well as their corresponding representations in both 12-hour and 24-hour formats.

Solution Approach:

1. Understanding the Formats:
- 12-hour clock: Uses a 12-hour cycle with "a.m." (ante meridiem) for morning and "p.m." (post meridiem) for afternoon/evening.
- 24-hour clock: Uses a 24-hour cycle, where times are represented from 00:00 to 23:59. There is no need for "a.m." or "p.m."

2. Converting Between Formats:
- From 12-hour to 24-hour:
- For times before 12:00 p.m., keep the same hour but add "0" if it's a single digit (e.g., 1:30 p.m. → 13:30).
- For times after 12:00 p.m., add 12 to the hour (e.g., 4:20 p.m. → 16:20).
- From 24-hour to 12-hour:
- For hours 00:00 to 11:59, use the same hour and mark it as "a.m."
- For hours 12:00 to 23:59, subtract 12 from the hour and mark it as "p.m."

3. Handling Specific Phrases:
- Quarter past: Adds 15 minutes to the hour.
- Twenty-two minutes to: Subtracts 22 minutes from the next hour.
- Twelve midnight: Represents 00:00.
- Quarter to: Subtracts 15 minutes from the hour.

Step-by-Step Solution:

#### Row 1:
- Time in words: Quarter past two in the afternoon
- 12-hour clock: 2:15 p.m.
- 24-hour clock: 14:15

#### Row 2:
- Time in words: Not provided.
- 12-hour clock: 7:00 p.m. (since 19:00 is 7:00 p.m.)
- 24-hour clock: 19:00

#### Row 3:
- Time in words: Twenty-two minutes to nine in the evening
- 12-hour clock: 8:38 p.m. (9:00 - 22 minutes)
- 24-hour clock: 20:38

#### Row 4:
- Time in words: Not provided.
- 12-hour clock: 4:20 p.m.
- 24-hour clock: 16:20

#### Row 5:
- Time in words: Not provided.
- 12-hour clock: 11:57 p.m. (since 23:57 is 11:57 p.m.)
- 24-hour clock: 23:57

#### Row 6:
- Time in words: Thirteen minutes past five in the morning
- 12-hour clock: 5:13 a.m.
- 24-hour clock: 05:13

#### Row 7:
- Time in words: Not provided.
- 12-hour clock: 1:35 a.m.
- 24-hour clock: 01:35

#### Row 8:
- Time in words: Eleven minutes to eight in the evening
- 12-hour clock: 7:49 p.m. (8:00 - 11 minutes)
- 24-hour clock: 19:49

#### Row 9:
- Time in words: Not provided.
- 12-hour clock: 3:25 a.m. (since 03:25 is 3:25 a.m.)
- 24-hour clock: 03:25

#### Row 10:
- Time in words: Not provided.
- 12-hour clock: 11:15 a.m.
- 24-hour clock: 11:15

#### Row 11:
- Time in words: Twelve midnight
- 12-hour clock: 12:00 a.m.
- 24-hour clock: 00:00

#### Row 12:
- Time in words: Not provided.
- 12-hour clock: 12:00 p.m.
- 24-hour clock: 12:00

#### Row 13:
- Time in words: Quarter to four in the afternoon
- 12-hour clock: 3:45 p.m.
- 24-hour clock: 15:45

#### Row 14:
- Time in words: Not provided.
- 12-hour clock: 12:20 a.m. (since 00:20 is 12:20 a.m.)
- 24-hour clock: 00:20

Final Answer:

\[
\begin{array}{|c|l|c|c|}
\hline
\# & \text{Time in words} & \text{12-hour clock} & \text{24-hour clock} \\
\hline
1 & \text{Quarter past two in the afternoon} & 2:15 \text{ p.m.} & 14:15 \\
\hline
2 & \text{Seven o'clock in the evening} & 7:00 \text{ p.m.} & 19:00 \\
\hline
3 & \text{Twenty-two minutes to nine in the evening} & 8:38 \text{ p.m.} & 20:38 \\
\hline
4 & \text{Four twenty p.m.} & 4:20 \text{ p.m.} & 16:20 \\
\hline
5 & \text{Eleven fifty-seven p.m.} & 11:57 \text{ p.m.} & 23:57 \\
\hline
6 & \text{Thirteen minutes past five in the morning} & 5:13 \text{ a.m.} & 05:13 \\
\hline
7 & \text{One thirty-five a.m.} & 1:35 \text{ a.m.} & 01:35 \\
\hline
8 & \text{Eleven minutes to eight in the evening} & 7:49 \text{ p.m.} & 19:49 \\
\hline
9 & \text{Three twenty-five a.m.} & 3:25 \text{ a.m.} & 03:25 \\
\hline
10 & \text{Eleven fifteen a.m.} & 11:15 \text{ a.m.} & 11:15 \\
\hline
11 & \text{Twelve midnight} & 12:00 \text{ a.m.} & 00:00 \\
\hline
12 & \text{Twelve noon} & 12:00 \text{ p.m.} & 12:00 \\
\hline
13 & \text{Quarter to four in the afternoon} & 3:45 \text{ p.m.} & 15:45 \\
\hline
14 & \text{Twelve twenty a.m.} & 12:20 \text{ a.m.} & 00:20 \\
\hline
\end{array}
\]

\boxed{
\begin{array}{|c|l|c|c|}
\hline
\# & \text{Time in words} & \text{12-hour clock} & \text{24-hour clock} \\
\hline
1 & \text{Quarter past two in the afternoon} & 2:15 \text{ p.m.} & 14:15 \\
\hline
2 & \text{Seven o'clock in the evening} & 7:00 \text{ p.m.} & 19:00 \\
\hline
3 & \text{Twenty-two minutes to nine in the evening} & 8:38 \text{ p.m.} & 20:38 \\
\hline
4 & \text{Four twenty p.m.} & 4:20 \text{ p.m.} & 16:20 \\
\hline
5 & \text{Eleven fifty-seven p.m.} & 11:57 \text{ p.m.} & 23:57 \\
\hline
6 & \text{Thirteen minutes past five in the morning} & 5:13 \text{ a.m.} & 05:13 \\
\hline
7 & \text{One thirty-five a.m.} & 1:35 \text{ a.m.} & 01:35 \\
\hline
8 & \text{Eleven minutes to eight in the evening} & 7:49 \text{ p.m.} & 19:49 \\
\hline
9 & \text{Three twenty-five a.m.} & 3:25 \text{ a.m.} & 03:25 \\
\hline
10 & \text{Eleven fifteen a.m.} & 11:15 \text{ a.m.} & 11:15 \\
\hline
11 & \text{Twelve midnight} & 12:00 \text{ a.m.} & 00:00 \\
\hline
12 & \text{Twelve noon} & 12:00 \text{ p.m.} & 12:00 \\
\hline
13 & \text{Quarter to four in the afternoon} & 3:45 \text{ p.m.} & 15:45 \\
\hline
14 & \text{Twelve twenty a.m.} & 12:20 \text{ a.m.} & 00:20 \\
\hline
\end{array}
}