Example 1

0 + 3

we begin at 0 and move 3 units to the right as shown below in red to get +3,

Also + 4 + 3 we stand at +4 then move 3 units to the right as shown in blue to get +7.

Example 2

0 - 3

we begin at 0 move 3 units to the left as shown in red below to get -3

while (-2) + (-3)

we open the brackets to get -2 - 3

then stand at -2 on the number line then move 3 steps to the left as

shown in blue to get -5.

Example 3

(+7) – (+5) =

first remove the brackets to get 7 - 5

stand on +7 on the number line then move 5 steps to the left as shown in blue below

that takes you to 2.

The answer is therefore 2.