Six Figure Grid Reference

Grid References 
Maps may be divided into numbered squares. These squares can be used to give a place a four or six-figure grid reference.

Four Figure Grid Reference
Maps have two sets of numbers tha are used for four figure grid reference. The numbers running along the bottom of the map are called eastings because they increase going to the east.
The numbers that fun along the sides of the map are called northings because increase from from south to north. These numbers combined (two eastings and two northings) will give four numbers telling the location of the object. These four numbers are the reason it is called four figure grid reference.

For example the location of the tree on the grid will use the easting (19) and the northing (43) to give the four figure 1943. The coordinates 1943 tells the box in which the tree is located.

For six figure grid reference, we need two more numbers to be more accurate. We can divide the grid into 10 and count the lines to find the two additional numbers. So the four figure coordinates are 1943.
We will leave spaces fpr the two extra numbers we will need for six figure reference like this 19_43_ .
The six figure grid reference for the tree is 196438. The 6 is found by counting along the eastings and the 8 is found by counting along the northings.