\(\text{100+300=400 600-200=400}\)

\(\text{123+154=277}\)

5x1=5 

5x2=10

5x3=15

5x4=20 

5x5=25

5x6=30

5x7=35

5x8= 40

5x9=45

5x10=50

\(\text{thomas edison}\)

\(100+20=120\)

\(\text{100 + 111 + 245 + 356 = 211 + 245 + 356 = 456 + 356 = 812}\)

\(100+111+245+356\)

 \(=211+601\)

 \(=812\)

100 + 111 + 245 + 356 x 5 + 365 

= 211 + 245 + 356 x ( 5 + 1 ) 

= 456 + 356 x 6

= 456 + 2136

= 2592

b

\(\text{2300m = 2 km 300 m}\)