How do I find a missing dimension in a dimension string?

The dimensions in a string add up to the overall dimension. Take the known ones away from the overall. In feet and inches, turn everything into inches first.

How far apart are two floor levels?

Take the lower level away from the upper one. FFL +6.000 and +3.150 are 2.850 m apart, which is 2850 mm.

Construction plans: lesson 5 of 6Harder

Work out dimensions and levels

Work out the missing dimension or the level difference and type it. Get 10 right to finish.

What is the missing dimension?

Worked examples

Feet and inches. A string reads 3'-6", ?, 4'-2" with an overall of 12'-0". In inches: 144 - 42 - 50 = 52 in, which is 4'-4". Type 4'-4".
Metric. A string reads 900, ?, 1250 with an overall of 4200. 4200 - 900 - 1250 = 2050. Type 2050.
Levels. FIN FLR 110'-8" above FIN FLR 100'-0" is 10'-8" higher. FFL +6.000 above FFL +3.150 is 2850 mm higher.

How to type the answer

Feet and inches: 4'-4", 4' 4 or 4 ft 4 in. Metric: 2050, or with a unit like2.05 m. If you are stuck after two tries, you can show the answer.

Questions

How do I find a missing dimension in a dimension string?: The dimensions in a string add up to the overall dimension. Take the known ones away from the overall. In feet and inches, turn everything into inches first.
How far apart are two floor levels?: Take the lower level away from the upper one. FFL +6.000 and +3.150 are 2.850 m apart, which is 2850 mm.

Explained in our own words and checked against several textbooks and trade school resources. Office standards vary, so always check the legend on your drawing set.