Question

21. What must be added to -9 to have a sum of 20?

Answer 1

Answer:

21C

22D

23B

24C

25A

Step-by-step explanation:

Answer 2

Answer:

21) c)29

22) d)57

23) b)-321

24) c)70

25) a)-10

explanation

let the unknown answer be x

21) x+(-9)=20

x-9=20

x=20+9

x=29

22)45-(-12)=x

45+12= 57

23)x×123 = -39483

x= -39483

123

x= -321

24) (30×3)+(-2×10)

90+(-20)

90-20=70

25) 5×-2=-10