Do the following calculations:
 $$(+7)+(3)=$$
 $$(5)+(2)=$$
 $$(+7)(+2)=$$
 $$(+9)(6)=$$
Development:

 They have different signs
 We calculate the absolute values of each number: $$+7=7,$$ $$3=3$$
 We subtract the absolute values: $$73=4$$
 We put the sign of the number with the greatest absolute value. In this case, $$7$$ is greater than $$3$$, therefore we put the $$+$$ sign: $$+4$$
 And so, the result is: $$(+7)+(3)=+4$$

 They have the same sign
 We calculate the absolute values of each number: $$5=5$$, $$2=2$$.
 We add up the absolute values: $$5+2=7$$
 We put the sign they had before: $$7$$
 So the result is: $$(5)+(2)=7$$

 The minuend is $$+7$$, and the subtrahend is $$+2$$.
 The opposite of $$+2$$ is $$2$$.
 We add up the minuend ($$+7$$) and the opposite of the subtrahend ($$2$$): $$(+7)+(2)=+5$$
 The result of the subtraction is $$(+7)(+2)=+5$$

 The minuend is $$+9$$, and the subtrahend is $$6$$.
 The opposite of $$6$$ is $$+6$$.
 We add up the minuend ($$+9$$) and the opposite of the subtrahend ($$+6$$): $$(+9)+(+6)=+15$$
 The result of the subtraction is $$(+9)(6)=+15$$
Solution:
 $$(+7)+(3)=+4$$
 $$(5)+(2)=7$$
 $$(+7)(+2)=+5$$
 $$(+9)(6)=+15$$