Let the first number be #n#
Then the four consecutive numbers are:
#n" ; "(n+1)" ; "(n+2)" ; "(n+3)#
So :#" "n+(n+1)+(n+2)+(n+3) = 26#
#=>4n+6=26#
Subtract 6 from both sides
#=>4n+6-6=26-6#
#4n+0=26-6" "#
#color(brown)("Notice that the above is the source method that gives the shortcut")#
#color(brown)("approach. Which is: for add and subtract, move it to the other side")#
#color(brown)("of the = and change the sign.")#
Divide both sides by 4
#4/4xxn=20/4#
But #4/4=1#
#n=5#
#color(brown)("Notice that the above is the source method that gives the shortcut")#
#color(brown)("approach. Which is: for multiply, move it to the other side")#
#color(brown)("of the = and divide by it. For divide, move it to the other side")#
#color(brown)("of the = and change it to multiply")#
If the first number is 5 then the numbers are:
#color(blue)(5 + 6 +7+ 8 = 26")#