In Numbers 1:20-43, you will read of the numbering of the tribes of Israel, excluding Levi, women, youth up to twenty years old, and those too old to fight in a war. The census gave these numbers: 
 
46,500 from Reuben 
59,300 from Simeon 
45,650 from Gad 
74,600 from Judah 
54,400 from Issachar 
57,400 from Zebulun 
40,500 from Ephraim 
32,200 from Manasseh 
35,400 from Benjamin 
62,700 from Dan 
41,500 from Asher 
53,400 from Naphtali 
 
Even without Levi, there were still twelve groups, because Joseph was divided into Ephraim and Manasseh. Numbers 3 provides the numbering of Levi. 
Therefore, a huge number of people came out of Egypt, but only a little more than 42,000 came out of Babylon, showing how much the Israelites had hurt themselves through repeated and insistent sin. 

Let us learn that God knows each of us, as He did each of the Israelites and that He expects the best we can do for Him.