Question

My calculator does not have a 3 key that works! How can I use this broken calculator to do 23 x 45.

Answer 1

Solution:-

$\longrightarrow$ This problem can be tackled by using distributive property of multiplication .

It states for any three numbers a,b and c

$\green{ \underline { \boxed{ \sf{(a±b)\times c = a \times c±b\times c}}}}$

Similarly,

$\quad$23 × 45

$\longrightarrow$(21+2) ×45

$\longrightarrow$21×45+2×45

$\longrightarrow$945 + 90

$\longrightarrow$ 1035

It can also be done as-

$\quad$23 × 45

$\longrightarrow$(25-2) ×45

$\longrightarrow$25×45-2×45

$\longrightarrow$1125-90

$\longrightarrow$ 1035