Related Clues:

• Very simple (colloq.)
• Say yes possibly when bit of food is brought in? That's certainly not difficult
• 'Knock yourself out'
• Like falling off a log (informal)
• "Fine by me" (last 3 letters ...)
• Simple, or a hint to the initials of each pair of starred clues' answers
• So simple ... like 17-, 24-, 40- and 52-Across?
• 'So simple!'
• Pee twice, say, when going off — it's that simple
• Simple as ABC or 123