# Upper and lower bound

##### Intros
###### Lessons
1. Introduction to upper and lower bounds
2. How to find the upper and lower bounds?
3. What is "Limits of accuracy"?
##### Examples
###### Lessons
1. Evaluating the Upper and Lower Bounds
Find the upper and lower bounds for each of the following scenarios:
1. The time it takes Dennis to finish a 1km-race is 130s, rounded to the nearest 10 seconds.
2. The size of a watch face measures 4cm to the nearest centimeter.
3. Thomas weighs 72.6kg, accurate to 1 decimal place.
4. The maximum speed of Kevin's car is 200mph, rounded to 1 significant figure.
2. Understanding the Limits of Accuracy
In Sylvia's garden, the average width of a willow tree trunk is 136cm while that of a maple tree trunk is 172cm, both numbers corrected to the nearest centimeter. Find the greatest possible difference in their widths.
1. A rectangle with length 7cm and width 3cm is given. If both sides are measured to the nearest cm, find the smallest possible area.
1. Michael takes 43s, to the nearest second, to finish a 400m sprint, measured to the nearest 10m. What is his fastest possible average speed?