Largest Even
Well done for giving clear solutions to this
problem. Many of you were able to explain a general strategy.
Tom and Jeevan from Devonshire Primary School said:
If you are trying to make the largest even number using an odd
number you put the odd number in the tens column and in the units
column you put $8$.
But if you're doing it with an even number then you put $9$ in the
tens column and then put the even number in the units column.
Peter, Henry, Charlie, Lulu and Samuel at
Weald C of E Primary School assumed that you could also get a zero.
They went on to think about how you would make the smallest
even number:
Largest Even
1.If you get an odd number, put an eight in the units column.
2.If you get an even number, put a nine in the tens column.
3.If you get a zero, put a nine in the tens column.
Smallest even
1.If you get an odd number, add a zero in the units column.
2.If you get an even number, add a one in the tens column
3.If you get a zero, put a one in the tens column.
Homeroom 7 at Kororoit Creek Primary School,
Australia looked at a strategy for making the largest odd number
too:
The largest two-digit odd number we could make is $97$. We
could not make $99$ because we only have one $9$.
If you pulled out an odd number first this should always go in
the 'ones' column. Unless you pull out a number $9$. The $9$ will
always go first because $97$ is the biggest number we can make.
e.g. $97$, $79$, $59$, $39$, $19$.
If you pull out an even number first it should always go in
the 'tens' columns, otherwise your two-digit number will not be
odd. You should still always choose the number $9$ as your second
card to make the largest number possible. e.g. $89$, $69$, $49$,
$29$.
Well done too to Robert from West Hoathly and
Sophie from Greenacre who also sent very full responses.