To determine how many more centimetres the plant needs to grow to reach 1 metre in height, you first need to convert 1 metre to centimetres.
1 metre = 100 centimetres.
The plant is currently 73 cm tall. To find out how much more it needs to grow:
100 cm - 73 cm = 27 cm.
The plant needs to grow 27 more centimetres to reach 1 metre tall.