Many fans of the fun probability game that is bingo prefer to play the North American version which uses 75 balls. This can be attributed to the fact there are all kinds of patterns one can win with. At the start of a 75-ball bingo game, the caller would specify the winning pattern for the respective round. There are all kinds of patterns callers can experiment with. Some are made to resemble letters and numbers, others are more intricate and look like different objects and even animals.
These patterns are fun but some of them are next to impossible to mark off on your bingo card, precisely because of their intricacy. More straightforward patterns like the Top, Middle, and Bottom pattern are far easier to complete.
Top, Middle and Bottom Pattern
The Top, Middle, and Bottom pattern is often called Layer Cake by seasoned bingo players so do not be confused when you encounter it under its bingo lingo name – both terms refer to the same thing. This pattern can be achieved only in the US variation of bingo, played with 75 balls because of the specifics of the grid it uses.
The tickets for this version of the game have 5×5 grids for a total of 24 random numbers, which range from 1 to 75. The word B-I-N-G-O is spelt on top of the ticket, with a letter placed above each column. The 75-ball bingo grids are short of one number because the third row is missing a number in its very middle so that there are only 4 numbers there instead of 5. This blank space can be used by players to complete a winning pattern, like the Top, Middle and Bottom one.
The name of the pattern is quite self-explanatory as it requires you to mark off all numbers from the top, middle, and bottom rows of your bingo ticket. Thus, you need five numbers to be called from the first tow, four called numbers on the third row, and five numbers on the fifth row. There is also a variation of the Top, Middle and Bottom pattern, called B-N-O Lines which is basically the same, only here you need five numbers to hit in your ticket’s B column, four from its N column, and five more from the O column.
Number of Calls for the Top, Middle and Bottom Pattern
Calculating the exact probability of covering specific patterns in bingo is quite complicated because there are too many factors that bear consideration. You need to know how many players would join the game, the overall number of tickets, and the number of purchased tickets. This information can help you figure out the odds of winning the game with a pattern.
The world’s biggest manufacturer of bingo products and equipment released statics on the average number of calls and winners for specific patterns, with results based on a computer simulation involving 70,000 games. According to these results, the average number of calls before a Top, Middle and Bottom pattern gets completed is 49.56 when 500 tickets are in play but drops to 42.81 when the total number of non-duplicate tickets increases to 6,000.