Muplication- Missing numbers- Mr Peter Sullivan

This activity can be found on P44/45 in Peter Sullivan’s book Challenging Mathematical tasks.

Pose this question.

I did a a multiplication question correctly on the computer, but my printer ran out of ink.

Now the question looks like this:

2_ x 3_ = _ _ 0

What might the digits that did not print be? Gove as many possibilities as you can.

Enabling:

1.  _ x _ = _0
2. 1_ x _ = _0

Extending:

Ask the students to convince you that they have all the possible solutions for the initial question

Extra questions:

1. 1_ x 4_= _ _ 2
2. _ _ _ divided by 4 = _ 6
3. Tell the students that when multiplied, two 2 digit numbers have an answer that ends in 5( units digit)
4. Tell the students that when multiplied, two 2 digit numbers have an answer that ends in 8( units digit
5. Using just the digits 3,4,5 and 6, what is the higest possible product?
6. 52_ x 3_ = _ _ _0

Enjoy!!

Run a discussion afterwards with groups or as a class.:

:)x