3dm-2m+2dm=......CM. Tolong Jwb Guys

3 dm = 3 x 10 = 30 cm
2 m = 2 x 100 = 200 cm
------------------------------- -
                       = -170 cm
2 dm = 2 x 10 = 20 cm
--------------------------------- +
                       = -150 cm

1dm = 10cm.
3dm = 3 × 10 = 30cm.
2dm = 2 × 10 = 20cm.

1m = 100cm.
2m = 2 × 100 = 200cm.

= 30 - 200 + 20.
= -150cm.