Multiplication by 10, 100, 1000

Age
6-9.

Materials

 * Decimal system materials
 * Paper
 * Black and red pencils

Preparation
This activity is a prerequisite for the small bead frame

Presentation

 * 1) The directress isolates a 10-bar.
 * 2) Directress asks the child; "How many units are there in 10?" 10.
 * 3) The directress isolates a hundred square and asks the child; "How many tens are there in 100?" "How many units?"
 * 4) Isolate the cube. Ask: "How many hundreds are there in 1000? How many units? tens?"
 * 5) "We can say that 10 tens is the same as 100, 100 tens is the same as 1000 and so on. "
 * 6) With the child draw relative conclusions of all the changes possible.

By ten 

Directress write down a multiplication problem and ask the child to lay out the problem, using the golden bead material i.e. ( 21 x 10 =).


 * 1) The child, knowing the function of multiplication, combines these quantities and makes the necessary changes.
 * 2) With the answer - two hundreds, one ten, and the zero is written in red. 21x10 = 210.
 * 3) Observe that the product is simply 21 (the multiplicand) with a zero after it.
 * 4) Do many examples of this type, including: 30 x 10 = 300

By one hundred


 * 1) Directress write down a multiplication problem such as 23 x 100 = and asks the child to lay out the material.
 * 2) We can't put out 23 one hundred times, we would run out of beads!
 * 3) We can multiply each unit by 100. Isolate one bead from the 23.
 * 4) 1 x 100 = 100 Substitute the bead for a hundred square.
 * 5) Repeat for the other two units. Then 10 x 100 = 1000.
 * 6) Replace each ten bar with a thousand cube, and so on.
 * 7) Record the product. 23 x 100 = 2300.
 * 8) Notice that the product has the same number of zeros as the multiplier.

By one thousand 


 * 1) Directress write the problem 4 x 1000 =.
 * 2) As before, multiply each unit by 1000, replacing each bead with a thousand cube.
 * 3) Record the product 4 x 1000 = 4000. In this case we jumped from the units, past the tens, past the hundreds, to the thousands.
 * 4) For each hierarchy that we increased, one zero was added.
 * 5) Observe as before that the number of zeros in the product is the same as the number of zeros in the multiplier.
 * 6) The product is simply the number of zeros in the multiplier.

Purpose
Direct Aim:


 * to be sure that the child has understood the concept of change
 * To ease of multiplying by powers of ten, and understanding of the characteristic patterns of such multiplication.

Indirect Aim:


 * To prepare the child for multiplication using the bead frames.