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How will we write the grams in the table above as kg?

I know 1 000 g = 1 kg

Thus: 1 g = 1 1 000 size 12{ { { size 8{1} } over { size 8{1`"000"} } } } {} kg= 0,001 kg

In the same way 17 g will be 17 thousandths of a kg.

17 g = 0,017 kg

and 234 g = 0,234 kg

4 387 g = 4 kg 387 g = 4,387 kg

1. Write the following as kg.

a) 9 g ............................

b) 26 g ............................

c) 89 g ............................

d) 436 g ............................

e) 2 309 g ............................

f) 5 006 g ............................

2. Study the different weight pieces below. Choose the fewest number of weights you will need to balance the scale and write them down.

Mass Weights needed
e.g. 1,010 kg 1 kg ; 10 g
1,023 kg ....................................................................................................
1,023 kg ....................................................................................................
1,007 kg ....................................................................................................
1,056 kg ....................................................................................................
983 g ....................................................................................................
724 g ....................................................................................................

4. Rounding off

4.1 Can you round off the following to the nearest kg?

(a) 7,6 kg .........................

(b) 0,5 kg .........................

(c) 4,2 kg .........................

(d) 2,5 kg .........................

4.2 Round off the following to the nearest ton:

(a) 20,8 t .........................

(b) 29,4 t .........................

(c) 1,5 t .........................

(d) 34,9 t .........................

BRAIN-TEASER!

You want to determine the mass of a chair. You have a bathroom scale, but the chair is too big for it and falls off. How can you determine the mass of the chair without using a bigger scale?

Assessment

LO 4
MeasurementThe learner will be able to use appropriate measuring units, instruments and formulae in a variety of contexts.
We know this when the learner:
4.1 reads, tells and writes analogue, digital and 24-hour time to at least the nearest minute and second;
4.2 solves problems involving calculation and conversion between appropriate time units including decades, centuries and millennia;
4.3 uses time-measuring instruments to appropriate levels of precision including watches and stopwatches;
4.4 describes and illustrates ways of representing time in different cultures throughout history;
4.5 estimates, measures, records, compares and orders two-dimensional shapes and three-dimensional objects using S.I. units with appropriate precision for:
  • mass using grams (g) en kilograms (kg);
  • capacity using millimetres (mm), centimetres (cm), metres (m) en kilometres (km);
  • length using. millimetres (mm), centimetres (cm), metres (m) en kilometres (km);
4.6 solves problems involving selecting, calculating with and converting between appropriate S.I. units listed above, integrating appropriate contexts for Technology and Natural Sciences;
4.7 uses appropriate measuring instruments (with understanding of their limitations) to appropriate levels of precision including:
  • bathroom scales, kitchen scales and balances to measure mass;
  • measuring jugs to measure capacity;
  • rulers, metre sticks, tape measures and trundle wheels to measure length.

Memorandum

ACTIVITY 1

ACTIVITY 2

Bathroom scale; spring balance; kitchen scale; balance/scale

1.

1.1: 6,25 kg

1.2: 88,5 kg

1.3: 3 kg

1.4: 17,68 kg

1.5: 210 g

1.6: 172 kg

2.

2.1: 3,050 kg

2.2: 5,710 kg

2.3: 1,215 kg

2.4: 0,604 kg

ACTIVITY 4

1. 1.1: 0,009

1.2: 0,026

1.3: 0,089

1.4 0,436

1.5 2,309

1.6 5,006

3.

MASS PIECES NEEDED
1 kg; 20 g; 2 g; 1 g
1 kg; 20 g; 5 g; 2 g; 1 g
1 kg; 5 g; 2 g
1 kg; 50 g; 5 g; 1 g
20 g; 10 g; 2 g; 1 g500 g; 200 g; 200 g; 50 g
500 g; 200 g; 20 g; 2 g; 2 g

4.

4.1

a) 8

b) 1

c) 4

d) 3

4.2

a) 21

b) 29

c) 2

d) 35

BRAIN-TEASER!

Stand on scale and take the reading; then hold chair above your head while on the scale and take reading again (or vive versa); the difference in the readings is the mass of the chair.

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Source:  OpenStax, Mathematics grade 5. OpenStax CNX. Sep 23, 2009 Download for free at http://cnx.org/content/col10994/1.3
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