# S-Cool Revision Summary

## S-Cool Revision Summary

## Rounding

Decimal Places - count from the decimal point

*Significant Figures*

- Count from the first digit.
- Don't count zeros unless they're in-between non-zero digits.

*Estimating*

- Use one significant figure unless you can be more accurate and still do it in your head.

*Error*

- Measurement is only approximate.
- The real answer can be half the rounded unit either way.
- We call them upper and lower bounds.

**Maximum values of calculations:**

- Addition and Multiplication - use all upper bounds.
- Subtraction and Division - first number upper bound, second number lower bound.

Vice versa for minimum values of calculations.

*Trial and Improvement*

- Use tables to display guesses and answers. Say whether too high or too low!
- Be methodical.
- If you know which two numbers the answer is between try the middle and that will tell you which one it is closer to.