In the multiplication calculation, some of the digits have been replaced by letters and others by asterisks. Can you reconstruct the original multiplication?
Age 7 to 11 Challenge Level:
This game is for you to play against the computer. However, you
could easily use your own calculators and adapt it to play away
from a computer.
The object of the game is to be the first to get exactly to
How to play:
Enter a 7-digit number into your calculator. You may use the
same digit more than once. The computer will also put a number into
A random number will appear at the top of the screen. If this
digit appears in the number you have on your calculator, you can
change that digit to zero by subtracting the appropriate number
using the calculator keys.
If you subtract the correct amount, this digit will
automatically change to zero. If you are incorrect, you will be
allowed another chance.
For every random number given, you can only remove one digit
from your calculator. So if you have, for example, four 3's you
must wait for 3 to come up four times.
The computer will do the same thing as you for each
The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the
NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to
embed rich mathematical tasks into everyday classroom practice.