number to multiply 6 times 4 because we saw that 10 wasn’t suitable.
Let’s try using 9 as our reference number.
Subtract crossways:
6 − 5 = 1
or
4 − 3 = 1
Multiply 1 by our reference number, 9:
1 × 9 = 9
Now multiply the numbers in the circles, and add the result to 9:
3 × 5 = 15
15 + 9 = 24
The full working looks like this:It certainly is not a practical way to multiply 6 times 4 but you see that we can make the formula
work if we want to. Let’s try some more.
Let’s try 8 as a reference number.
Let’s try 7 as a reference number.Let’s try 3 as a reference number.Let’s try 2 as a reference number.