21-26 only quickly i need answer quickly

21 - 
There are 1000 m in 1 km.
441.96/1000 = 0.44196
0.44196 km

22 - 
There are 1000 mg in 1 g.
5700/1000 = 5.7
5.7 g

23 - 
There are 1000 mL in 1 L.
0.946 * 1000 = 946
946 mL

24 - 
There are 10 mm in 1 cm.
60(10)=600
600/50=12
12 beads

25 - 
There are 1000 mL in 1 L.
1500(2)=3000
3000/1000=3
3 L

26 - 
There are 100 cm in 1 m.
110(100)=11000
11000-8=10992
10992 cm

21.  1,000 meters = 1 kilometer
441.96 meters = 0.44196 kilometer

22.  1,000 milligrams=1 gram
5,700 milligrams= 5.7 grams

23.  1 liter = 1,000 milliliters
0.946 liter = 946 milliliters

24.  10 millimeters = 1 centimeter
50 millimeters = 5 centimeters
60/5 = 12 sections between beads

25.  1,000 milliliters = 1 liter
1,500 milliliters = 1.5 liters
double 1,500 milliliters = double 1.5 liters = 3 liters

26.  100 centimeters = 1 meter
8 centimeters = 0.08 meter
Difference = 110 meters - 0.08 meter = 10,992 centimeters

Much better than that . . . How many pygmy pines would it take
to stack up to one redwood ?

110 / 0.08 = 1,375 of them, stacked top to bottom.

You're welcome.