Here is a big stack of blocks

You would have to count to a million if wished to count all of the blocks in a stack as the one illustrated in this drawing

The bottom layer of tiny blocks would have
 100 in each of 100 rows

1,000,000 blocks

a million of them
 
There would be 100 such layers.
  
How many in 100 layers?
Do you think there are a million grains in a bushel of wheat?
    
Of course, you see only a few of the blocks 

this stack --- those on the outside.
 
Believe it or not there are about 5,000,000 grains
in a bushel of wheat.