Cobol has introduced many new intrinsic functions, unless you are running a very old version of cobol you should have these. Make sure you are using the latest compilers, if your source code will not compile with these functions then you are using an old compiler (and many companines still are as even the old compilers and hardware stilll work great).

ACOS
ANNUITY
ASIN
ATAN
CHAR
COS
CURRENT-DATE
DATE-OF-INTEGER
DATE-TO-YYYYMMDD
DATEVAL
DAY-OF-INTEGER
DAY-TO-YYYYDDD
DISPLAY-OF
FACTORIAL
INTEGER
INTEGER-OF-DATE
INTEGER-OF-DAY
INTEGER-PART
LENGTH
LOG
LOG10
LOWER-CASE
MAX
MEAN
MEDIAN
MIDRANGE
MIN
MOD
NATIONAL-OF
NUMVAL
NUMVAL-C
ORD
ORD-MAX
ORD-MIN
PRESENT-VALUE
RANDOM
RANGE
REM
REVERSE
SIN
SQRT
STANDARD-DEVIATION
SUM
TAN
UNDATE
UPPER-CASE
VARIANCE
WHEN-COMPILED
YEAR-TO-YYYY
YEARWINDOW

This site provides a list of interesting subjects, tips, and tricks. Although it is mostly computer tips, there are also tips and tricks related to various other helpful topics besides just computers. If you have an important tip that you think should be listed, feel free to post it below. Although I still take tips via email, I often scan and review posts on the page below and prefer that method.