Can anyone tell me how bets are denominated on the S+P 500 and the DJIA?

Is it per point, 1/10 of a point, or 1/100 of a point with these indices?

I've read in one place that a Spreadbet on the S+P is /0.01 and in another place that it's /0.1.

Thanks.

On IG Index Dow is per point