Upper and Lower Bounds

A length is given as $5.2$ cm, rounded to $1$ decimal place. Find the lower and upper bounds.

• 1The rounding unit is $0.1$ (the size of $1$ decimal place). Half of that is $0.05$
• 2Lower bound = $5.2-0.05=5.15$
• 3Upper bound = $5.2+0.05=5.25$

Answer: Lower bound = $5.15$ cm, Upper bound = $5.25$ cm

A mass is given as $340$ $g$, rounded to the nearest $10$ $g$. Find the lower and upper bounds.

• 1The rounding unit is $10$. Half of that is $5$
• 2Lower bound = $340-5=335$
• 3Upper bound = $340+5=345$

Answer: Lower bound = $335$ $g$, Upper bound = $345$ $g$