`13.5 xx 16.3 xx 12.8 = ?`

Some equations are solved on the basis of a certain system. Find the correct answer for the unsolved equation on that basis. 5 xx 8= 28,3 xx 7 = 12,8 xx 6 = 35, 13 xx 13 = ?

A student follows the rule 3 xx 3 + 3 xx 3 = 12 , 4 xx 4 + 4 xx 4 = 16, 5 xx 5 + 5 xx 5 = 20, then find the value of the expression 12 xx 12 + 12 xx 12 according to this rule.

A student follows the rule 3 xx 3 + 3 xx 3 = 12, 4 xx 4 + 4 xx 4 = 16 , 5 xx 5 + 5 xx 5 = 20 , then find the value of the expression 12 xx 12 + 12 xx 12 according to this rule.

If 5 xx 7 = 5, 12 xx 3 = 6, 8 xx 9 = 2 what is the value of 6 x 8 = ?

A Class-III student perform multiplication of 16 xx 25 as follows 16 xx 25 = 8 xx 2 xx 5 xx 5 = 8 xx 5 xx 2 xx 5 = 40 xx 10 = 400 Which property of multiplication has the student used in this question?

Simplify: (i) 5/12 xx (-36) , (ii) -17/18 xx 12 , (iii) -5/6 xx 6/5 , (iv) -14 xx 9/28 , (v) -12/5 xx (-15) , (vi) -3/4 by 8/7 , (v) -16/9 by 12/-5 , (vi) 35/(-8) by 12/(-5) (vii) -3/10 by -40/9 , (viii) -32/5 by 15/(-16) , (ix) -8/15 by -25/32