(please i need help)(brainiest of the Brainiest)Which expression has a value of -10?

1. −3×5−(−8)

2. −2×5−20

3. 4×(−3) + 10÷5

4. −5+(−2)+22÷(−2)

Name the most appropriate metric unit for each measurement like the mass of cow

Which is the standard form for this number? (4 x 1 100 ) + (8 x 1 1,000 ) + ( 3 x 1 100,000 ) ? a) 0.004803 b) 0.04803 c) 0.0483 d) 0.483

Two customers went to a post office. first customer paid $12 for 14 and 5 envelopes the second paid 24.80 for 10 postcards and 15 envelopes. what is cost of each envelope?