a) 834-a=20*4 b) 400:t=48+32

Here are the solutions with quick steps:

a) 834 - a = 20 * 4

• 20 * 4 = 80
• 834 - a = 80
• a = 834 - 80 = 754

b) 400 : t = 48 + 32

• 48 + 32 = 80
• 400 : t means 400 / t
• 400 / t = 80 → t = 400 / 80 = 5

Answers: a = 754, t = 5.