Question

8km+15dam=?m
52hm-110dam?m
8m+124dm?cm
70dm+18cm=?mm
3000

Answer 1

5200-1100=4100 m
800=1240=2040 cm
7000+180=7180 mm

Answer 2

$8 \ km+15 \ dam=8000 \ m+150 \ m=\boxed{8150 \ m} \\ 52 \ hm-110 \ dam=5200 \ m-1100 \ m=\boxed{4100 \ m} \\ 8 \ m+124 \ hm=800 \ cm+1240000 \ cm=\boxed{1240800 \ cm} \\ 70 \ dm+18 \ cm=7000 \ mm+180 \ mm=\boxed{7180 \ mm}$