Jawaban:

1. a. 240

b. 324

c. 138

d. 72

e. 120

2. a. 180

b. 242

c. 255

d. 380

e. 228

f. 378

g. 225

h. 1.271

i. 704

j. 2.178

Penjelasan dengan langkah-langkah:

1. a. 20×(5+7) = (20×5)+(20×7) = 100+140 = 240

b. 12×(11+16) = (12×11)+(12×16) = 132+192 = 324

c. 6×(8+15) = (6×8)+(6×15) = 48+90 = 138

d. 8×(18-9) = (8×18)-(8×9) = 144-72 = 72

e. 10×(24-12) = (10×24)-(10×12) = 240-120 = 120

2. a. 9×(8+12) = (9×8)+(9×12) = 72+108 = 180

b. 11×(15+7) = (11×15)+(11×7) = 165+77 = 242

c. 15×(20-3) = (15×20)-(15×3) = 300-45 = 255

d. 20×(24-5) = (20×24)-(20×5) = 480-100 = 380

e. (10+9)×12 = (10×12)+(9×12) = 120+108 = 228

f. (12+15)×14 = (12×14)+(15×14) = 168+210 = 378

g. (17-8)×25 = (17×25)-(8×25) = 425-200 = 225

h. (20+21)×31 = (20×31)+(21×31) = 620+641 = 1.271

i. (25+19)×16 = (25×16)+(19×16) = 400+304 = 704

j. 22×(100-1) = (22×100)-(22×1) = 2.200-22 = 2.178

semoga membantu, maaf kalau salah dan jadikan sebagai jawaban tercerdas ya :)