Answer :
Solution:-
[tex]\longrightarrow[/tex] This problem can be tackled by using distributive property of multiplication .
It states for any three numbers a,b and c
[tex]\green{ \underline { \boxed{ \sf{(a±b)\times c = a \times c±b\times c}}}}[/tex]
Similarly,
[tex]\quad[/tex]23 × 45
[tex]\longrightarrow[/tex](21+2) ×45
[tex]\longrightarrow[/tex]21×45+2×45
[tex]\longrightarrow[/tex]945 + 90
[tex]\longrightarrow[/tex] 1035
It can also be done as-
[tex]\quad[/tex]23 × 45
[tex]\longrightarrow[/tex](25-2) ×45
[tex]\longrightarrow[/tex]25×45-2×45
[tex]\longrightarrow[/tex]1125-90
[tex]\longrightarrow[/tex] 1035