One and three-quarters + two and one-third = one and three-quarters × two and one-third for sixth grade

One and three-quarters + two and one-third = one and three-quarters × two and one-third for sixth grade

4:2 1 + 1:7 2 = 4:2 * 1:7 2
The rule is that the numerator of two numbers is the same, the denominator of two numbers is equal to the numerator, and the sum of two numbers is equal to the multiplication of two numbers

1 + 1 / 2 + 1 / 3 + 2 / 3 + 1 / 4 + 2 / 4 + 3 / 4 +. + 1 / 10 + 2 / 10 + 9 / 10=

1+1/2+(1/3+2/3)+(1/4+2/4+3/4)+...+(1/10+2/10+...+9/10)
=1+0.5+1+1.5+2+2.5+3+3.5+4+4.5
=1+(0.5+4.5)×9÷2
=1+45÷2
=23.5 (because the fraction is not convenient to express, it is converted to decimal)
Hope to help you!