Clare Curran, sitting in front of Jackson, turned around and muttered something.
Kieran McAnulty sitting nearby pulled out an iPad mini and started frenetically tapping, presumably into Google, but Goldsmith beat him to it.
Goldsmith: "For the minister's information the average wage is nearly $60,000, 28 per cent increase on nine years ago."
He then asked what Jackson's target was for increasing the average wage.
Jackson's defence to being caught out was to come back fighting: "Our target is to create real jobs with dignity amongst our community. This is an Opposition that has forgotten a big group of people in New Zealand, the Maori nation and the Pacific Island nation. Shame on you!"
Next time Jackson will be better prepared.
The large National Opposition gets about two thirds of the 12 questions daily on notice to ministers and up to 38 follow-up questions with no notice which is where the real danger lies for ministers not on top of the basics of his or her portfolio.
Jackson was the not the only minister who learned a lesson today.
Revenue Minister Stuart Nash was about to deliver a first reading speech on the Taxation (Neutralising Base Erosion and Profit Shifting) Bill during the hubbub of MPs departing the chamber after Question Time.
He sat down momentarily - or for what he thought was momentarily - when Speaker Trevor Mallard ruled he had forfeited his speech for sitting down at the wrong time.
Mallard, who clashed daily with National last week, seemed determined to achieve some balance and to upset the Government today.
It worked.
Leader of the House Chris Hipkins demanded to know the basis of his ruling.
"Astonishing," is how Winston Peters described it.
Nash sought the leave of the House to give his speech anyway but it took only one person to object and National's Gerry Brownlee did.
According to House observer Graeme Edgeler, the same thing happened to a new minister in 2008 who was unfamiliar with how to move a first reading. That minister was Gerry Brownlee – but leave was moved by Labour to let him do it anyway and it was granted.