# GMC2: Estimating, calculating and error spotting

This list contains a collection of resources to help meet General Mathematical Competency 2 (GMC2). More resources to support T level Science can be found on our T Level science resource packages page.

**GMC2 states:**

Students should:

- Be able to estimate lengths, areas and volumes to aid error spotting.
- Be able to estimate the approximate answer to a calculation to aid error spotting.
- Know when rounding a value to a specific place value or to a number of significant figures is appropriate in addition to being able to perform the skill.
- Be aware of the errors caused by inappropriate rounding
- Appreciate why the use of rounded values in subsequent calculations can cause significant errors in the final solution.
- Be able to work with error bounds, max and min values and calculate percentage error
- Deal with small and large numbers expressed in standard form
- Be able to calculate the rate of reaction: amount of reactant or product/time

### Estimation, Assumptions and Predictions

This presentation begins with twelve sheets of questions for quick revision of calculations involving rounding to significant figures. This is followed by a set of slides of questions which involve more challenge and could lead to group discussion. Slide twenty-five has a link to a YouTube presentation of Fermi Estimation and this is followed by four short problems to be solved. The question of climate change is then raised and students have the opportunity to make decisions about estimates and evaluate the data in order to make predictions

### Estimating Length Using Standard Form N4

In this resource students learn to interpret decimals using metric units, estimate lengths of real life objects and interpret standard form. They will also discuss and understand these processes. Some students will have encountered decimals and standard form before. The opening discussion is used to recall these ideas

### Estimation and Approximation

Estimation and approximation covers: rounding to the nearest 10,100,100, rounding to significant figures, rounding to decimal places, estimating calculations by rounding to one significant figure, use of brackets and the memory function on a calculator, rounding errors, upper and lower bounds.

The initial file forms part of the textbook. The activities sheet, extra exercises and mental tests compliment the work covered in the textbook. The overhead slides can be used on an interactive whiteboard.

Alongside the pupils' material there are lesson plans which outline the content of the unit, these are differentiated into three levels, ST, A and E as well as suggested routes through them.

### Errors *suitable for home teaching*

The ‘Errors’ resource contains examples that can be used to:

• find the upper and lower bounds of measurements, given the level of accuracy used

• consider how possible errors accumulate in formulae that involve measurements.