Chapter 7.6 (Mathematics 5)

Subtraction of decimals up to thousandths

Subtraction of decimals

Group Activity 4

In pairs, work out: 9.3 – 6.2

  1. Represent 9.3 in an abacus.
  2. Remove 2 rings in the tenths.
  3. Remove 6 rings in the ones place value.
  4. Count the number of rings remaining in tenths and ones place value.
  5. Discuss the results and share with other groups.

Example 7

Work out 2.1 – 0.9

2.1 – 0.9 = 1.2

Example 8

Work out: Subtract 2.180 from 3.453

Thousandths: 3 – 0 = 3
Hundredths: 5 – 8 not possible
Regroup 1 tenths to 10 hundredths
Hundredths: 5 + 10 = 15 hundredths
Hundredths: 15 – 8 = 7 hundredths​
Ones: 3 – 2 = 1 ones​​​​

Exercise F

F1

Work out:

F2

Work out:

F3

Work out:

  1. 0.241 from 0.783
    The result is .
  2. 1.312 from 3.855
    The result is .
  3. 2.05 from 3.148
    The result is .
  4. 2.139 from 17.76
    The result is .

6.55 l  5.84 l =  l

15.5 l  12.25 l =  l

2.56 l  0.75 l =  l