Jackson Carlaw said data showed the performance in the two subjects has 'never been lower'.
On Scotland Tonight, the SNP leader was also quizzed on indyref2 and her domestic record.
Denise Findlay was expected to investigate general election candidate Neale Hanvey.
All the main UK-wide parties have now revealed their pitches to voters ahead of December 12.
The debate will be broadcast live on STV at 8pm on Tuesday night.
Nicola Sturgeon, Jackson Carlaw, Richard Leonard and Willie Rennie went head-to-head.
Jackson Carlaw has ruled out the prospect of indyref2 during Boris Johnson's premiership.
The First Minister is expected to make the comments in a speech to party activists on Saturday.
An Ipsos MORI survey found 44% of voters will pick Nicola Sturgeon's party on December 12.
The party is pledging 'no to indyref2' as its pitch to voters ahead of the December 12 poll.