if i have 436 x 67 how do I get the product by subtracting?

Question

My daughter has this problem:

 

Laura found 67 x 436 by multiplying and subtracting. Show how Laura found the product. I showed my daughter the multiplication method and then used division for the subtraction. Was this right?

Answer 1

Hi, Barb.

I do not know the particular method this assignment is looking for, but here is one way to get the product using mutiplication and subtraction:

Round 67 to 70.

Multiply 436 x 70, which is an easier multiplication problem.

Since 70 is 3 more than 67, this product has 3 extra "436"s. From the product, subtract 436 three times.

436 x 70 = 30,520

30,520 -436 = 30,084

30,084 -436 = 29,648

29,648 -436 = 29,212

 

Answer 2

67 x 436

= 436 x (70-3) <== since 67 = 70 - 3

= 436 x 70 - 436 x 3 <==Multiplication and subtraction

= 30520 - 1308

= 29212