Calculate Total Distance: Adding 1.2, 2.1, and 1.7 Kilometers in a Three-Day Journey

Andy goes on a three-day trip.

On day one, he travels $1.2$ km.

On day two, he travels $2.1$ km.

On day three, he travels $1.7$ km.


How many kilometres does Andy travel in total over the three days?

To work out how many kilometres Andy walks in total, we need to add up the distances he walks each day in the following manner:

$1.2\\+2.1\\+1.7$

First we will add the digits after the decimal point accordingly:

$2+1+7=10$

Since these add up to 10, we can replace the tenths digit with a 0 and add a units digit to the number.

Now, simply add up the units digits of the number (the original digits before the decimal place plus our new one):

$1+1+2+1=5$

In total, Andy walks 5 km (5.0 km).