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1.2 Addition

ADDITION: ADDING TO A SUM OR TOTAL

Addition is used when combining items, or putting items together to obtain a total. It helps answer questions such as "How many?" "How much?" or "How far?" Let's look at different ways that addition can be used. Some words used often to refer to addition are "plus", "and", "the sum of", "total", or "added to".

Example 1 - Pedro's crew has 4 pulaskis. Jane's crew has 6 pulaskis. How many pulaskis do they have together?

Addition Chart

As shown the the figure above, the addition needed to answer this question is: 4 + 6 = 10.
 

ADDITION IS USED IN COMBINING DISTANCES OR LENGTHS.

Example 2 - Crew 1 constructs 14 chains of handline on the day shift. Crew 2 constructs 11 chains of handline on the night shift. How many chains did crew 1 and 2 construct altogether?

14 chains + 11 chains = 25 chains

 

ADDITION IS USED TO FIND THE DISTANCE AROUND AN OBJECT.

The total distance around an object is called the perimeter.

Example 3 - The Division Supervisor (DIVS) used two dozers to construct a line. The dozers cleared a line of the following shape. How many chains of dozer line were constructed?
 

Addition Chart

45 chains + 36 chains + 28 chains + 29 chains + 110 chains = 248 chains

 

ADDITION IS USED IN COMBINING AREAS.

Example 4 - The day shift had two spot fires that were contained at 6 acres and 8 acres each. What was the total area of the spot fires that burned during the day shift?

6 acres + 8 acres = 14 acres

 

ADDITION IS USED IN COMBINING VOLUMES.

Example 5 - Herman pumped 30 gallons of fuel into one tank, 25 gallons into the next tank, and 27 gallons into the last tank. How many gallons of fuel did Herman pump?

30 gallons + 25 gallons + 27 gallons = 82 gallons

 

ADDITION IS USED IN COMBINING LARGER NUMBERS.

When adding several numbers, especially large numbers, add the ones (1s) first, then the tens (10s), then the hundreds (100s), and so on.

Example 6 - Add: 548 + 365
First, add the ones. There are 13 ones, or 1 ten and 3 ones. Write 3 in the ones column and "carry over" the 1 above the tens.
Next, add the tens. There are 11 tens, or 1 hundred and 1 ten. Write 1 in the tens column and the 1 above the hundreds.
Now, add the hundreds. There are 9 hundreds.addition of large numbers
The answer to 548 + 365 is 913.

ADDING POSITIVE AND NEGATIVE NUMBERS

Numbers can be positive or negative. Positive numbers are indicated with a + sign, or have no sign. If a number is written without a sign, the sign is assumed to be positive. Negative numbers are indicated with a - sign. For example, a negative pressure may be indicated as -25 inches of Hg, or as a vacuum of 25 inches of Hg. 

Signs are important in adding numbers. Here are some easy rules to help determine the sign of a sum: 
image tag sign rules for addition

Example 7 - Adding numbers with like signs.
5 + 5 = 10
3 + 3 = 6
-5 + (-5) = -10
-3 + (-3) = -6
 

Example 8 - Adding numbers with unlike signs. Notice that the sign of the larger number is the sign that the answer will have.
5 + (-3) = 2
3 + (-3) = 0
3 + (-5) = -2
2 + (-3) = -1

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Date: Sept 11, 2025
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The S-219, Firing Operations (Blended) course is now available on the Wildland Fire Learning Portal. Developed through the Incident Performance and Training Modernization (IPTM) effort, this training supports individuals working towards Firing Boss, Single Resource (FIRB) incident qualifications.

This blended course combines online and instructor-led training to provide students with the knowledge and skills required to perform the duties of the FIRB, as described in the NWCG Incident Position Standards for Firing Boss, Single Resource, PMS 350-105.

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The NWCG Mental Health Subcommittee (MHSC) and Risk Management Committee (RMC) recognize the unique challenges and demands faced by the wildland fire community. The MHSC and RMC know that we are all stronger together and believe in fostering a culture of support, understanding, and resilience.

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NWCG is excited to announce the launch of the Incident Performance and Training Modernization (IPTM) Story Map, a new interactive resource that showcases how NWCG is transforming wildland fire training and qualifications through a performance-based system.

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NWCG is excited to announce that the S-290, Intermediate Wildland Fire Behavior (Blended) training is now available on the Wildland Fire Learning Portal. S-290 (Blended) training combines online training and instructor-led training components that support individuals working towards any Single Resource Boss or Fire Effects Monitor incident qualifications.

This second course in the series collectively serves to develop fire behavior prediction knowledge and skills, and provides more detailed information on fuels, weather, and topography that affect wildland fire behavior for safety purposes.

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