Hey guys. This is going to sound silly, but I am so confused as to how to figure out the combined calorie amount of something.
For example, tonight my mom made pasta. She had premade sauce, but then added a can of tomatos to it.
Here are the facts:
The sauce is 75 calories for 1/2 a cup. There are 25 ounces in the can.
The tomatoes are 25 calories for 1/2 a cup. There are 14.5 ounces in the can.

Do I average the 75 & 25? My mom tried to figure it out, and she did this whole big complicated math problem, then got that there was 260 cals in 1/2 a cup, so we knew that was wrong. Can anyone explain the correct way to do this? Thanks!!

I am not a math expert (and not even a true calorie counter, lol)I just find i fit in better here since i'm not on any of the mentioned "organized" plans..but I would guestimate it..I would say around 60cals for 1/2 cup..
Look at it this way..it's going to be between 25 and 75 cals because its a blend of the 2 items..the higher calorie item is belnded at almost a 2:1 ratio to the lower calorie item..so it would be higher than 50cals and less than 75...
you could just average the 75 and 25 IF the amounts were the same. The 75 cal item is in a 2:1 ratio to the other so it's not a straight averaging..lol
OMG I hope that response wasnt too confusing..
LOng story short, I would guess 60 or 65 calories and not bother with the equation.

Tomato Sauce - 150 calories per cup x 3.125 cups (which is ounces converted to cups) = 468.75 calories total of tomato sauce.

Canned tomatoes - 50 calories per cup x 1.8125 cups (again, converted) - 90.625 calories total of tomatoes

3.125 cups of tomato sauce plus 1.8125 cups canned tomatoes = total volume of sauce mixture: 4.93 cups. That means the number of half cup servings is double that, or 9.875.

So we have 468.75 calories of sauce added to 90.625 calories of tomatoes (total calories: 559.375) divided by 9.875 half cup servings.

Grand total: about 56.645 calories per serving.

(sorry, can't resist a math problem)

Here's what I got:

Combined, there are 6.25 servings of the sauce and 3.625 servings of the tomatoes.

So, the sauce has 468.75 calories and the tomatoes have 90.625 calories, for a combined total of 559.375 calories.

I see someone else also did this

I figured that out too -- except I took into account the unequal proportion of tomatoes to sauce. There is more sauce and less tomatoes (63% sauce, 37% tomatoes) -- it's not too far from 50/50 -- but it would increase the calorie count -- I'm not delving into percentages and ratios (too late), so I'd estimate the additional calories at 15. So about 70 calories.

One cup = 8 ounces (fluid....1/2 cup = 4 ou).
Sauce .4 ounces= 75 cals / 25 ou in a can dividied by .4 ou (1/2 cup) = 6.25 1/2 cup servings. 6.25 times 75 cal= 468 cals per can of sauce
Tomatoes 14.5 ounces divided by 1/2 cup (.4 ounces)=3.6 servings 3.6 times 25 cals = 90 cals per can.
Added together 558 total cals divided by 9.85 (1/2 cup servings) = 56.85 cals per 1/2 cup.
I'm not a math pro either. Next time save the labels- combine all the information into fitday and it will give you the correct tally. MUCH easier!

There is a total of 39.5 ounces in both cans. That means the proportion of tomatoes is 14.5/39.5 and the proportion of sauce is 25/39.5. You then multiply the calories by the proportion to come up with calories per half cup.

75 calories x 25/39.5 = 47.47
25 calories x 14.5/39.5 = 9.18
total calories = 56.65 per 1/2 cup.

this is what I do.

go to http://www.fitwatch.com/database/analyzer.php
enter my ingrediants and amounts.

you will get all the info right in front of you.
hope this helps