Single Digit + Single Digit	Single - Single	Double + Single	Double - Single
100 3 + 1 = 4	100 7 - 3 = 4	100 11 + 8 = 19	100 10 - 3 = 7
200 6 + 7 = 13	200 8 - 7 = 1	200 15 + 6 = 21	200 21 - 8 = 13
300 4 + 8 = 12	300 22 + 7 = 29	300 34 - 7 = 27
400 2 + 5 = 7	400 9 - 6 = 3	400 37 + 9 = 46	400 45 - 9 = 36
500 9 + 8 = 17	500 9 - 8 = 1	500 59 + 8 = 68	500 67 - 6 = 61

Single + Single

How many teams are playing ?
Time given to answer each question ?