Importance of Estimating in Real

Life

A lot of everyday maths is about estimating quantities and I will be talking about some strategies including Kinect that can be used to develop a sense of number considered a very basic arithmetic skill needed to estimate.

Forest Way Teaching Alliance 2nd October 2015

• essential life skill

• make judgements

• can save time & money

• uses mathematical knowledge & reasoning

• enables us to check reasonableness of calculations .

‘front end’ estimates e.g. 575+ 324= 900

• provides fun & rich & maths activities

Do we give it enough importance ?

• skills of estimating develop over time and practice

• learners need to develop sense of number, physical quantity, & units of measure

• need a comparison

• need to understand context • challenges

Learning to estimate is dependent on the acquisition of very early

arithmetic skills

To develop sense of number is to be able to enumerate small quantities then progress to finding out how many without counting each individual object.

a

b

c

d e f

Jars Small containers same width as the jars

Count items in small container – use multiples of 10

Point out the height of the items in the small container.  Then speculate “how high” the large jar is in comparison to the height you measured in the small container. 

Model the height of the small container using fingers. Learners do the same to ‘count’ height of the large jar, and then count in 10’s to get to the approximate answer.

Show that 3 and a half small containers stacked up would equal the height of the large jar so 10+10+10+5=35 would be approximately how many were in the jar.

Describe capacity using own words

Fill containers with liquid or objects to show capacity approx. half full, nearly full, nearly empty or use fractions

Calculate approx. quantity in containers using the approach in previous slide.

A giraffe is about 5m tall

Estimate the height of the bus.

Estimate height of young giraffe

1 kg

medium

49p

£1 £1

£3.50

50p

60p

£1. 35

Kinect

Use technology to provide engaging opportunities to practise estimation and support relationship between estimation and numbers by embodying the relationship in whole body movement along a a virtual number line.

Relationship between learner’s movements and number tracked and presented on screen by P. Choak’s specially designed program for Kinect.

a b c

d e f

f

http://www.mathsisfun.com/numbers/estimation-game.php

http://resources.oswego.org/games/Estimate/estimate.html

http://www.iboard.co.uk/iwb/Estimate-and-Count-Marbles-402

‘Interactive investigation estimating different capacities in unusually shaped containers.  These widgets engage visual learners who may struggle with text-based or traditional teacher-led lessons.For kinaesthetic learners, a range of open-ended investigations and problem-solving tasks link mathematics to the real world.’

References

BBC Skillwise website Estimating & Rounding.

Nasen Special 3/12 An Educated Guess

Number Sense Series: Developing Early Number Sense –nrich.maths.org