we know that
Number line refers to a mathematical process of solving the equation with the use of lines.
we have
[tex] 235 + 123 [/tex]
Starting from [tex] 0 [/tex] you count [tex] 1 [/tex] up to [tex] 235 [/tex]. Then starting from [tex] 235 [/tex] you additionally count another [tex] 123 [/tex].
Then from zero start counting the total number to the line you stopped when adding [tex] 123 [/tex] to [tex] 235 [/tex].
This simply equals to
[tex] 235+123=235+(100+20+3)\\ =335+20+3\\ =355+3\\ =358 [/tex]
see the attached figure to better understand the problem
