give three ways a student could find the product of 9x7 if she had not memorized this fact.
Add nine 7's
Multiply 3 times 7. Multiply that answer by 3.
Multiply 10 times 7 and subtract 9.
Also -- remember that the digits of any product of 9 and another number add up to 9 or a multiple of 9.
Examples: 18, 27, 36, etc.
1. Add nine 7's
2. Multiply 3 times 7. Multiply that answer by 3.
3. Multiply 10 times 7 and subtract 9.
4. put your seven finger down and count on both sides and put the numbers together
There are several ways a student could find the product of 9x7 if they have not memorized this fact. Here are three possible methods:
1. Repeated Addition: The student can add 9 to itself seven times. This can be done by starting with 9 and adding it to itself repeatedly until seven times. For example: 9 + 9 + 9 + 9 + 9 + 9 + 9 = 63.
2. Number Line: The student can use a number line to visually represent the multiplication. They can start at 0 and jump in increments of 9 seven times. For example: 0, 9, 18, 27, 36, 45, 54, 63. The final count on the number line will be the product of 9x7, which is 63.
3. Arrays: The student can draw an array using rows and columns to represent the two numbers being multiplied. They can draw 9 rows and 7 columns or vice versa. Then, count the number of dots in the array. For example, by drawing 9 rows and 7 columns, the student will have 63 dots in the array, which is the product of 9x7.
To find the product of 9x7 without memorizing the fact, here are three methods a student could use:
1. Repeated Addition: The student can add the number 7 to itself nine times. For example: 7 + 7 + 7 + 7 + 7 + 7 + 7 + 7 + 7 = 63. This method is time-consuming but helps in understanding the concept of multiplication as repeated addition.
2. Number Line: The student can use a number line to represent the multiplication equation. Start at 0 and make jumps of size 7 nine times. Count the final number to find the product. For example: 0, 7, 14, 21, 28, 35, 42, 49, 56, 63.
3. Arrays: The student can draw an array or a grid with 9 rows and 7 columns. Then count the total number of cells to find the product. For example:
X X X X X X X
X X X X X X X
X X X X X X X
X X X X X X X
X X X X X X X
X X X X X X X
X X X X X X X
X X X X X X X
X X X X X X X
Counting the X's, we get a total of 63, which is the product of 9x7.
These methods are useful when students haven't memorized multiplication facts and help in understanding the underlying concept of multiplication.