I've read this and just don't understand what ds is being asked to do. This is exactly what the sheet says:
"Doubles over 10
To work out these doubles:
- double the first number
- double the second number
- add the two answers together!
Double 12
+ = _
+ = _
+ = _ "
Do they mean the first line is 12 + 12 = 24, then 24 + 24 = 48, then add 24 + 48 to make 72? There are six questions like this in total, and the largest number is 63 - seems a bit hard for a 6 year old?