Convert Metric Units of Length

Convert Metric Units of Length exercise

• Can you complete the table?

  Hints

  Recall the abbreviations:

  • km = kilometers
  • m = meters
  • cm = centimeters
  • mm = millimeters

  To find the number of meters in 1 kilometer, multiply 1 by 1,000.

  To find the number of centimeters in 1 meter, multiply 1 by 100.

  To find the number of millimeters in 1 centimeter, multiply 1 by 10.

  Solution

  1 km (kilometer) = 1,000 m (meter)

  1 m (meter) = 100 cm (centimeter)

  1 cm (centimeter) = 10 mm (millimeter)

• Can you find the equivalent lengths?

  Hints

  Remember:

  1 km (kilometer) = 1,000 m

  1 m (meter) = 100 cm

  1 cm (centimetre) = 10 mm (millimetres)

  If you are converting from a smaller unit to a larger unit, use division.

  • 200 cm to m - divide 200 by 100 to get 2 m.

  If you are converting from a larger unit to a smaller unit, use multiplication.

  • 2 m to cm - multiply 2 by 100 to get 200 cm.

  For example, if we are looking for a matching pair for 400 mm, we can divide 400 by 10 to convert to cm.

  400 $\div$ 10 = 40

  As another example, if we are looking for a matching pair for 80 cm, we can multiply 80 by 10 to convert to mm.

  80 x 10 = 800

  Solution

  • 400 mm = 40 cm 400 $\div$ 10 = 40
  • 80 cm = 800 mm 80 x 10 = 800
  • 4 m = 400 cm 4 x 100 = 400
  • 8 km = 8,000 m 8 x 1,000 = 8,000
  • 8,000 mm = 800 cm 8,000 $\div$ 10 = 800

• Can you convert the lengths?

  Hints

  Remember:

  1 km (kilometer) = 1,000 m

  1 m (meter) = 100 cm

  1 cm (centimetre) = 10 mm (millimetres)

  To convert meters to centimeters, multiply by 100.

  To convert meters to kilometers, divide by 1,000.

  To convert centimeters to millimeters, multiply by 10.

  Solution

  Peter measured the length of his garden to be 12 meters. This would be 1,200 centimeters.

  • Multiply 12 by 100 to convert 12 meters to 1,200 centimeters.

  ${}$

  Logan is running 5 kilometers for charity. This is 5,000 meters.

  • Divide 5,000 by 1,000 to convert 5,000 meters to 5 kilometers.

  ${}$

  The pencil is 190 millimeters. This is 19 centimeters.

  • Multiply 19 by 10 to convert 19 centimeters to 190 millimeters.

• Can you put the lengths in order?

  Hints

  Convert all lengths to the same unit to make comparison easier.

  Remember:

  1 km (kilometer) = 1,000 m

  1 m (meter) = 100 cm

  1 cm (centimeter) = 10 mm (millimeters)

  For the first set, convert all length to millimeters by multiplying the lengths in centimeters by 10.

  You can then order these lengths: 120 mm, 145 mm, 100 mm (10cm), 120 mm and 130 mm (13 cm).

  Solution

  1.10 cm, 120 mm, 13 cm, 140 mm, 145 mm

  If we convert all lengths to mm (by multiplying lengths in cm by 10), we get:

  • 100 mm (10 cm x 10)
  • 120 mm
  • 130 mm (13 cm x 10)
  • 140 mm
  • 145 mm

  _________________________________________________

  2.1,000 m, 2 km, 2,200 m, 2,700 m, 3 km

  3.1 m, 114 cm, 1,400 mm, 2 m, 201 cm

• How many metres is 600 centimeters?

  Hints

  1 m = 100 cm

  To convert centimeters (cm) to meters (m), divide by 100.

  For example, if we were converting 700 cm to m, we would divide 700 by 100.

  700 $\div$ 100 = 7

  700 cm = 7 m

  How many meters in 600 cm?

  Solution

  The correct answer is 6 m.

  To convert centimeters to meters, we divide by 100.

  600 $\div$ 100 = 6

• What could the length be?

  Hints

  Convert all of the lengths in the question to metres to work out the range of possible answers.

  • 5 km = 5,000 m
  • 12,000 mm = 12 m
  • 3, 800 m = 3,800 m
  • 2,100 cm = 21 m

  We can now see that possible answers will fall between 21 m and 3,800 m.

  Convert the possible answers to meters, which ones fall between 21 m and 3,800 m?

  There are 4 possible answers.

  Solution

  The possible answers are:

  • 2,200 cm
  • 3 km
  • 395 m
  • 2,900 m

  If we convert all of the measurements in the question to metres we get:

  • 5 km = 5,000 m
  • 12,000 mm = 12 m
  • 3,800 m = 3,800 m
  • 2,100 cm = 21 m

  From this, we can see that possible answers will fall between 21 m and 3,800 m. If we convert the correct possible answers to metres, we get:

  • 2,200 cm = 22 m
  • 3 km = 3,000 m
  • 395 m = 395 m
  • 2,900 m = 2,900 m

  The incorrect answers convert to:

  • 220 cm = 2.2 m
  • 4 km = 4,000 m
  • 22 mm = 0.022 m
  • 1,900 cm = 19 m