Q. 43.7( 3 Votes )
Shown below is a method to the product 46× 28.
i) Check this method for some other two-digit numbers.
ii) Explain why this is correct, using algebra. (Recall that any two-digit number can be written 10m + n, as seen in the section, Two-digit numbers of the lesson, Numbers and Algebra, in the class 7 textbook).
Answer :
i)
ii) We know that we can express any 2-digit number as 10m+n , where m is the digit at tens place and n is the digit at ones place.
So, let (10m+n) and (10x+y) be the two numbers to be multiplied.
(10m+n)(10x+y) = 10m(10x+y)+n(10x+y) = 100 mx +10my +10nx + ny
= (100× mx) + ((m×y)+(n×x))× 10 +(n×y)
Now, carefully observe the above method, you will see that we were finding these terms only and then addition of these terms gives us the required product.
Rate this question :
Champ Quiz | Algebric Identities46 mins
Discussion on Algebric Identities48 mins
Algebric Expressions and Identities45 mins
Algebraic Expressions and Identities43 mins
Master Algebraic Identities43 mins
Division of Algebraic Expressions36 mins
Smart Revision | Quiz on Algebraic Expression and Identities44 mins
How to Use Algebraic Identities40 mins
Genius Quiz | Algebraic Expressions and Identities30 mins
Multiplication of Algebraic Expression40 mins
Write number like this:
As in the calendar; mark four numbers in a square and find the difference of diagonal products. Is it the same for all squares of four numbers?
Kerala Board Mathematics Part IIn the multiplication table made earlier, take a square of nine numbers, instead of four, and mark the numbers at the four corners:
What if we take a square of sixteen numbers?
Kerala Board Mathematics Part IWrite number like this:
Instead of a square of four numbers, take a square of nine numbers and mark only the numbers at the four corners.
What is the difference of diagonal products? Explain using algebra.
Kerala Board Mathematics Part IWrite number like this:
As in the calendar; mark four numbers in a square and find the difference of diagonal products. Is it the same for all squares of four numbers?
Kerala Board Mathematics Part IWrite number like this:
Instead of a square of four numbers, take a square of nine numbers and mark only the numbers at the four corners.
What is the difference of diagonal products? Explain using algebra.
Kerala Board Mathematics Part IWrite number like this:
Explain why this is so, using algebra.
Kerala Board Mathematics Part IIn the multiplication table made earlier, take a square of nine numbers, instead of four, and mark the numbers at the four corners:
What if we take a square of sixteen numbers?
Kerala Board Mathematics Part IIn the multiplication table made earlier, take a square of nine numbers, instead of four, and mark the numbers at the four corners:
What is the difference of diagonal sums?
Kerala Board Mathematics Part IWrite number like this:
Explain why this is so, using algebra.
Kerala Board Mathematics Part I