Undercover - In China - Book 7

Part 11 - Math Tip Number Nine

After Judo we had mathemagics with Professor Smolkin, usually known as Anti Smolkin. In addition to our normal lesson he had a bonus.

 'Some of you are still having trouble multiplying by nine quickly,' Professor Smolkin began. 'So I want you to learn some mathemagics.  Are you all ready to rhomboid?'

Boz stuck a hand in the air. 'What's a rhomboid?'

'It is the quadrilateral equivalent of a rumba,' Anti replied, 'so don't forget your pink tutus. Now, back to the exciting stuff. Mambo number nine. I mean . . . math tip number nine.' 

 'You might just memorize, 9, 18, 27, 36, 45, 54, 63, 72, 81 and 90.'

'Yes! The nine times multiplication table. Notice that the two digits in each number add up to 9! This works for any number divisible by nine. Simply add all the digits in the number. If the total is 9, or 18, or 27 etc. the number is divisible by 9 or 3. 

 So, for example,' - he wrote on the blackboard - '234 and 972 and 6,217,281 are all exactly divisible by 9, because all the digits add up to 9 or 18 or 27 etc.'

A funny blue-green light obliterated the work on my monitor so I was not totally surprised when a line of brightly coloured tetrahedrons bounced across the screen. Each one had two eyes, a big grin and a placard with slogans like No Smolkin! Stop Smolkin NOW! I remembered these cartoon character had first appeared when Yonnie and Treeka had help us to escape from the Bunglers. Students stopped talking as all the computers showed the same spectacle and we all giggled until Professor Smolkin came back to look. 

 'No, not again,' he groaned as he peered at one of the screens. 'There's got to be an explanation for this phenomena,' he said. 'Someone's hacked into the school server.' The tetrahedrons were fading into a blue light leaving a message, SMOLKIN IS BAD FOR YOUR HELTH.

 'Who did this?' Professor Smolkin snarled. 'Someone who can't spell health . . . BOZWELL!'

Boz had wore his "who me?" expression. 'I didn't do it,' he said indignantly. 'I've been set up.' But he was still smirking.

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After school Miguel and I went to Licia place for pizza and, as soon as she switched her computer on, Yonnie and Treeka appeared looking grim faced. 

 'Did you crash the helicopter in Hong Kong?' I asked.

Yonnie giggled. 'No-ooh. The South China Morning Post has an article about a mysterious helicopter that terrified Hong Kong residents before landing at the airport with no one on board. They called it the Mary Celeste of the skies.' 

 Treeka interrupted. 'Mother Mandia says Dr Zhang is planning to use Murga's software to run several experiments but she suspects Murga has planted a Trojan horse to control her. She is trying to disable the virus before she has to use the software but is worried.'

'We should tell Dr Zhang,' I said.

Treeka said, 'Mandia has already argued with him, but he is convinced it is safe to use. He thinks Mandia is being paranoid and is just looking for an excuse not to work on the experiments.'

'Call Denny,' Licia suggested. 'See what he thinks.

'Yonnie instantly connected us with Denny Vernier, Dr Zhang's partner and chief engineer, via Skype.

'Hey Denny,' Miguel said. 'Do you know about Murga's software? What do you think?'

'Hey guys. What do I blooming think? Mandia's right. I don't trust Murga any further than I could throw him and Mandia doesn't trust him either.   However . . . Lee Zhang has a bee in his bonnet and swallowed Murga's sweet talk. He's going ahead anyway.'