28 x 2/7 = <<28*2/7=8>>8 students were absent last Monday.

So, 28 - 8 = <<28-8=20>>20 students were present last Monday.

# Answer

20
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
There are 28 students in a class. Two-sevenths of them were absent last Monday. How many students were present last Monday?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
20
There are 28 students in a class. Two-sevenths of them were absent last Monday. How many students were present last Monday?
train