hi I'm Ashley and welcome to multiplying unknown numbers in this video we will
practice solving for the unknown in multiplication problems are you ready
let's go in order to solve for an unknown in multiplication problems it's
important to understand the concept of fact families first notice here I have a
multiplication and division set of fact families so I have 2 times 3 equals 6
switch those around I have 3 times 2 equals 6 then 6 divided by 3 equals 2
and 6 divided by 2 equals 3 so I could use that to solve for an unknown in this
way let's say I have five times an unknown number equals 15 well how would
I figure that out what I could do is I could use this as the beginning number
in a division problem so 15 divided by our first number five is equal to what
well our number here is going to be the number we can fill in the blank up at
the top so 15 divided by 5 I know equals 3 so if I know that then I know 5
times 3 is equal to 15 let's apply that with a few problems from our game
my first problem here I have two times an unknown equals 8 so what I want to do
to solve for this unknown is flip these numbers around into a division problem 8
divided by 2 is equal to what ain´t divided by 2 equals 4 so 4 is our answer
and we could plug that in and check it if we want 2 times 4 you know your facts
equal 8 and that is correct let's try another one
all right now I have 2 times an unknown equals 34 now if I flipped that around
34 divided by 2 hmm that's not part of my division facts
that I've memorized yet so let me see let me solve this another way 34 divided
by 2 this way 2 goes into 3 how many times 1 2 times 1 is 2
I will subtract 3 minus 2 is 1 bring down my 4 and then 2 goes into 14 how
many times 7 so here is my final answer 17 34 divided by 2 equals 17 now I can
check my work so we said that our answer was 17 I'm going to check it by
multiplying 17 by 2 just see if I get 34 so 2 times 7 is 14
and then 2 times 1 is 2 1 more makes 3 34 so I know
I was correct great job you have learned how to solve for an unknown in
multiplication problems as you play the game the numbers will get progressively
larger and again on our multiplying unknown numbers to game there will also
be some larger more challenging problems but just remember you can solve them the
same way with our fact families now go practice what you've learned with our
online games and quizzes and remember to always be clever