Ray's New Practical Arithmetic · Arts. 135–136 · Unit 11: Decimal Fractions
64. Writing and reading decimals
Goal: Your child writes decimals from words and reads decimals aloud, naming the right-hand order.
You'll need
- The book
- A slate, small whiteboard or scrap paper
- A notebook and pencil
What's in the book
Rules for writing decimals, with worked examples and a long list of decimals to write; then rules for reading decimals, with worked examples. The exercises to read continue at the top of p. 175, just before Reduction of Decimals.
The lesson, step by step
Warm-up
Mental: Read aloud .5, .25, .125. Which is largest?
Naming a decimal
Read:
The numerator of a decimal is the number it expresses disregarding the decimal point.
The name of the right hand order is the name of the decimal.
Writing
Read the rule:
Write the numerator as an integer.
Place the decimal point so that the name of the right-hand order shall be the same as the name of the decimal.
Work the book's examples:
Write two hundred and sixty-five thousandths.
Write two hundred and sixty-five millionths.
(.265 and .000265: ciphers fill the empty places.)
Mixed numbers
Read:
In a mixed number, the decimal point is placed after the units order of the integer (Ex. 4).
Notice the book's trick in problems 33 and 34: "Two hundred and twenty-five thousandths" is .225, while "Two hundred units and twenty-five thousandths" is 200.025. The word "units" marks where the whole number ends.
Reading
Read:
Disregarding the decimal point, read the number as an integer.
Give the name of the right hand order.
Your child reads the first numbers of the reading list on p. 175 aloud.
Independent practice
Your child writes problems 5 to 40 in figures (spread over two days if needed).
Check and wrap-up
The writing list has no printed answers; see below. Mental: write 4 and 5 hundredths (4.05).
Answers to the book's problems
5. .26 6. .35 7. .87 8. 4.19 9. .005 10. .054 11. .304 12. 7.293 13. 25.047 14. .0205 15. .4125 16. .00009 17. .900 18. .00605 19. .20304 20. .000007 21. .000203 22. .300004 23. .0000024 24. .0080006 25. .000200 26. .00000002 27. .00000907 28. .20020003 29. 1.010100 30. .01010001 31. 106.037 32. 1.001 33. .225 34. 200.025 35. .002929 36. 2900.000029 37. 1.000005 38. .0000000202 39. 200.0000002 40. 65.006005 Where the words could be read two ways, these follow the book's own convention shown in 33 and 34: unless the word "units" appears, the whole phrase before the decimal name is the numerator.
Worked out for this site from the scan. If a number in your copy differs, trust the book.