Ray's New Practical Arithmetic · Art. 71 · Unit 7: Reduction of Compound Numbers

38. Time measure

Goal: Your child knows the table of time, which years are leap years, and reduces times to smaller or larger units.

⏱ About 30 minutes · 6 steps

Open it at the Internet Archive ↗

You'll need

  • The book
  • A slate, small whiteboard or scrap paper
  • A notebook and pencil

What's in the book

The table of time from seconds to centuries, the rules for leap years, the lengths of the months, then 11 reduction problems with printed answers.

The lesson, step by step

  1. Warm-up

    Mental: minutes in 2 hours? Hours in 3 days? Days in 4 weeks?

  2. The table

    Read the table aloud: 60 seconds 1 minute, 60 minutes 1 hour, 24 hours 1 day, 7 days 1 week, and on to years and centuries.

    Time Measure is used in measuring time.

  3. Leap years

    Read:

    Every year whose number is not divisible by 4 consists of 365 days.

    Every year whose number is divisible by 100, but not by 400, consists of 365 days.

    Ask: Was 1900 a leap year? (No.) 2000? (Yes.) This year?

  4. Work one

    Together:

    Reduce 2 hr. to seconds.

    2 × 60 = 120 min.; 120 × 60 = 7200 sec.

  5. Independent practice

    Your child does problems 2 to 11. Problem 4 has a neat answer:

    Reduce 9 wk. 6 da. 10 hr. 40 min. to minutes.

  6. Check and wrap-up

    Answers are printed (problem 4 is 100000 minutes). Say the months-rhyme or count knuckles to remember which months have 31 days.

Tip

In this table a month (mon.) means 4 weeks, so in problem 5, 1 mon. 3 da. is 31 days. (When finding time between dates, later, the book counts a month as 30 days.)

@teddyrookbook GitHub