Mathematical Literacy Level 2 Module 5

Mathematical Literacy NQF 2 Downloaded from hlayiso.com Maths Lit NQF Level 2

Estimating and measuring Module 5 Downloaded from hlayiso.com Maths Lit NQF Level 2

Overview 5.1 Estimating length, mass, volume and temperature 5.2 Using measuring instruments accurately Downloaded from hlayiso.com Maths Lit NQF Level 2

Estimating length, mass, volume and temperature Unit 5.1 Definition An estimate is a measure that is close to the actual measurement. • If you estimate well, you can: ” • select the right measuring instrument and unit • look in the correct range for an answer • realise immediately when your measurement or calculation is wrong. • find a strategy to solve a problem. Downloaded from hlayiso.com Maths Lit NQF Level 2

Estimating length Unit 5.1 • To estimate a length, you need to know the lengths of some common objects. • Then compare the unknown length to something you know. • Examples: • a matchbox (about 4 cm) • your hand (about 15 cm to the fingertips) • a ruler (30 cm) • your height (e.g. 1,7 m) • distances that you travel often Downloaded from hlayiso.com Maths Lit NQF Level 2

Estimating mass or weight Unit 5.1 • Find out the masses of some objects you can use to compare. • The size of the object does not determine its mass! • Then compare the unknown mass to something you know. • Examples: • ant (about 5 mg) • paperclip (about 1 g) • teaspoon of sugar (about 5 g) • loaf of bread (about 800 g) • large brick of margarine (500 g) Downloaded from hlayiso.com Maths Lit NQF Level 2

Estimating mass or weight Unit 5.1 Examples: • a 5 litre container of juice (5 kg) • a brick (2,5 kg) • a refrigerator (100 kg) • a small car (1 tonne) Downloaded from hlayiso.com Maths Lit NQF Level 2

Estimating volume and capacity Unit 5.1 • Find out the volumes of some objects you can use to compare. • Then compare the unknown volume to something you know. • Examples: • teaspoon (5 ml) • 1 tablespoon (15 ml) • 1 cup (250 ml) • a can of cold drink (300 ml) • a bottle of milk (1 litre) • a petrol tank (60 litres) • a bath (300 litres) Downloaded from hlayiso.com Maths Lit NQF Level 2

Estimating temperature Unit 5.1 Three important temperatures to remember: • z • Water freezes at 0°C (zero degrees Celsius) • A normal human body temperature is 37°C • Water boils at 100°C • We can use these temperatures to estimate other temperatures. • For example, a glass of cold water is much colder than body temperature, but not as cold as ice. It is between 4°C and 15°C. Downloaded from hlayiso.com Maths Lit NQF Level 2

Example 5.1 a) Unit 5.1 Downloaded from hlayiso.com Maths Lit NQF Level 2

Example 5.1 c) Unit 5.1 Downloaded from hlayiso.com Maths Lit NQF Level 2

Exercise 5.1 Unit 5.1 Complete Exercise 5.1 on page 89 of your Student’s Book Downloaded from hlayiso.com Maths Lit NQF Level 2

Using measurement instruments accurately Unit 5.2 An A analogue measuring digital measuring instrument instrument often needs you to read a scale gives a read-out of the accurately. measurement. Downloaded from hlayiso.com Maths Lit NQF Level 2

General rules for measuring Unit 5.2 Here are some important guidelines for using scaled instruments: Use the correct measuring instrument for the purpose. For example, don't use a ruler marked in cm if you need mm measurements. Line up to zero, or have a reading of zero at the beginning. Check that you know what the numbered units and the marked intervals between them represent. Your eyes must be directly in line with the place where you are taking the measurement. Take a reading and record the digits marked. Downloaded from hlayiso.com Maths Lit NQF Level 2

Measuring length: rulers, measuring tapes Unit 5.2 millimetres cm centimetres • A standard ruler is 30 centimetres long. • A ruler usually shows millimetre markings between the centimetres. • 10 mm = 1 cm Downloaded from hlayiso.com Maths Lit NQF Level 2

Measuring length: rulers, measuring tapes Unit 5.2 • 100 cm = 1 m • A metre ruler is 100 cm long. x 100 x 10 metres centimetres millimetres ÷100 ÷ 10 Downloaded from hlayiso.com Maths Lit NQF Level 2

Steps in measuring length Unit 5.2 1 What is the unit of measurement marked on the ruler or measuring tape? What unit does each marking show? 2 3 Align one end of the object to the zero mark. Read the measurement off the instrument to the number of digits that are clear. 4 5 If necessary, estimate one decimal place past what you can read. Write down the reading. Downloaded from hlayiso.com Maths Lit NQF Level 2

Example 5.2 b) page 91 Unit 5.2 Measure the length of the blue line to the nearest half centimetre. Downloaded from hlayiso.com Maths Lit NQF Level 2

Example 5.2 b) page 91 Unit 5.2 • The unit on this ruler is centimetres. It is marked off in half centimetres (0,5 cm) and millimetres. • The zero is in line with the beginning of the blue line. • The line is a bit more than 8,5 cm long. • The line is about 2 mm beyond the 0,5 cm marking. • We can estimate the reading as 8,7 cm. Downloaded from hlayiso.com Maths Lit NQF Level 2

Exercise 5.2 Unit 5.2 Complete Exercise 5.2 on page 93 of your Student’s Book Downloaded from hlayiso.com Maths Lit NQF Level 2

Measuring volume: measuring jugs and cups Unit 5.2 • Choose the cup or jug with the measurement you want. • Scoop or pour the ingredient or liquid in up to the level of the marking you want. • Pour some out or add some in until the measurement is exactly right. • The surface of a liquid is curved. Take your reading at the bottom of the curve. Downloaded from hlayiso.com Maths Lit NQF Level 2

Example 5.3 a) page 91 Unit 5.2 a) A chef is making a recipe that needs 875 ml of flour. How should he measure out the volume using standard measuring cups? • Measure using the full cup of 250 ml. 250 + 250 + 250 = 750 ml (3 cups) • Subtract the amount already measured from the total. 875 - 750 = 125 ml This is half a cup. • Write down the measuring cups used: 3½ cups Downloaded from hlayiso.com Maths Lit NQF Level 2

Exercise 5.3 Unit 5.2 Complete Exercise 5.3 on page 94 of your Student’s Book Downloaded from hlayiso.com Maths Lit NQF Level 2

Measuring mass: scales Unit 5.2 • Mass is measured in grams or kilograms using scales. • Here, a circular scale and a linear scale both read 670 g. • Bathroom scales usually read mass in kg from 0 to 120 kg. • Kitchen scales usually read mass in grams up to 500 g or 1 000 g. Downloaded from hlayiso.com Maths Lit NQF Level 2

Measuring mass: scales Unit 5.2 1 When measuring the mass of an object, remember: Begin by setting the scale to zero. Turn the knob on a mechanical scale, or reset the button on a digital scale. Follow the same rules we have listed so far to read the scale. 2 3 If the object needs to be in a container, find and record the mass of the empty container first. Find the mass of the container and the object together. Then subtract the mass of the container to get the mass of the object. 4 Downloaded from hlayiso.com Maths Lit NQF Level 2

Example 5.4 a) page 90 Unit 5.2 a) Take the mass reading on this scale at a vegetable shop. • The scale is marked in kg and g. • The numbered markings are 500 g apart and there are 100 g markings in between. • The certain measurement is 1 700 g. • The pointer looks like it is halfway between 1 700 and 1 800, so we can estimate the reading as 1 750 g. Downloaded from hlayiso.com Maths Lit NQF Level 2

Exercise 5.4 Unit 5.2 Complete Exercise 5.4 on page 96 of your Student’s Book Downloaded from hlayiso.com Maths Lit NQF Level 2

Measuring temperature Unit 5.2 • Mercury and alcohol thermometers show the temperature with a column of liquid. The liquid rises with a higher temperature because the liquid expands. • A clinical thermometer is marked from 35 degrees Celsius to 42 degrees Celsius. • It is designed to read small changes in a patient's temperature. Downloaded from hlayiso.com Maths Lit NQF Level 2

Example 5.5 a) Unit 5.2 Downloaded from hlayiso.com Maths Lit NQF Level 2

Example 5.5 b) Unit 5.2 Downloaded from hlayiso.com Maths Lit NQF Level 2

Exercise 5.5 & 5.6 Unit 5.2 Complete Exercise 5.5 & 5.6 on page 98 and 99 of your Student’s Book Downloaded from hlayiso.com Maths Lit NQF Level 2

Module assessment Module 5 Complete Module assessment on page 100 of your Student’s Book Downloaded from hlayiso.com Maths Lit NQF Level 2

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