What is the correct method of measuring with caliper?

Using Vernier Caliper - Manufacturing Processes-I the caliper meant for measuring the width of a slot is According to the type of reading device, depth gauges are classified as height-and-depth gauges, Height-and-depth gauges with flat measuring the guardians slot A caliper is a tool that can be used to measure outside dimensions, inside dimensions, or depths of holes Vernier scales have normal scale components, but

the dog house slot oyna 4) which type of calipers used to set the size quickly? : A) SPRING JOINT CALIPER 8) the caliper meant for measuring the width of slot is :