It is minus ten.
It is: 2.4+100+100 = 202.4
Five plus five equals ten.
Ten hectograms is equal to one kilogram.
One of ten equal parts would be a tenth.
Nought plus twelve. One plus eleven. Two plus ten. Three plus nine. Four plus eight. Five plus seven. Six plus six !
When Chuck Norris says so. Oh, it's riddle... When putting gloves on, then removing them, I guess.
Seven eights plus three eights is ten eights. Now, possibly you intended to ask about eighths, rather than eights. Ten eighths is equal to one and a quarter. However, ten eights is equal to 80. The extra h makes a difference.