Question

$15 - 3 \: \ \: 1\2 - 5 \: \: \: \: \: 1\2$
please solve it ​

Answer 1

15 - 31 - 51

= 15 - (31 + 51)

= 15 - 82

= -67

Answer 2

15-31-51
=15-(31+51)
=15-82
= -(-15+82)
= -(82-15)
= -(67)
= -67