If we multiply 40 with -8/15, so that the product will be 24.
Answers
Answer:
How do we multiply by a single digit?
multiplication
Align the multiplier (on the bottom) with the ones digit of the multiplicand (on top), and draw a line. Then multiply each digit of the multiplicand. Write the ones digit of each product below the line.
If there is a tens digit, carry it -- add it -- to the next product.
"7 times 8 is 56." Write 6, carry 5.
"7 times 2 is 14, plus 5 is 19." Write 9, carry 1.
"7 times 6 is 42, plus 1 is 43." Write 43.
That is,
7 × 628 = 4396.
Why can we repeatedly add 628 in that way? Because we have distributed 7 to the Tens, Ones, Hundreds of 628, and then added those partial products:
multiplication
When the multiplier has more than one digit --
multiplication
-- follow the same procedure for each digit. When we multiply by 3 tens, the product is 1884 tens. It is not necessary to write 18840. (Lesson 2.) Simply begin the 4 of 1884 in the tens column.
When we multiply by 2 hundreds, the product is 1256 hundreds, and so we write 6 in the hundreds column.