It's really easy to learn the size of your body. My span is around than 20 cm. 5 of them is 1 meter. the width of my pinky is 1 cm. You can learn how to step 1m distance, for me it's a bit longer than a normal step. I can measure with my body between 1cm and several meters. So it's really easy to overcome this small limitation of the metric system.
It's as easy as getting comfortable with the usual measures of your body. I also know how much is a kilogram because I can lift a big water bottle which also is a liter. Really, the way all of the units are built more or less around water can give you a pretty accurate instinct.
It's really easy to learn the size of your body. My span is around than 20 cm. 5 of them is 1 meter. the width of my pinky is 1 cm. You can learn how to step 1m distance, for me it's a bit longer than a normal step. I can measure with my body between 1cm and several meters. So it's really easy to overcome this small limitation of the metric system.
It's as easy as getting comfortable with the usual measures of your body. I also know how much is a kilogram because I can lift a big water bottle which also is a liter. Really, the way all of the units are built more or less around water can give you a pretty accurate instinct.