count the number of lines that start with the number

Shell Programming and Scripting
1

I have a file with contents similar to this.

abcd
1234
4567
7666
jdjdjd
89289
9382
92
jksdj
9823
298

I want to write a shell script which count the number of lines that start with the number (disregard the lines starting with alphabets)

2 
grep -c "^[0-9]" file