Adding three 3-digit numbers

Difficulty Starter · Set symbjw

Fill in what you can and press Check. Nothing you type is sent anywhere.

1
980776+616
2
305824+159
3
991399+141
4
339996+443
5
544352+376
6
836878+468
7
473736+494
8
289180+261
9
150958+580
10
783958+517
11
203721+839
12
644647+263
13
532783+143
14
183734+741
15
403800+414
16
311108+819
17
981875+307
18
814259+753
19
259130+928
20
899592+186

What is in this set

The numbers in this set run from 101 to 999.
Every problem in it will stack more than two numbers.
A careful solution takes 5 written steps on average.
The mistake this set invites most often, in 100% of the problems: only the first two addends were added — the third column never joined in.
Answers are a whole number.

Drawing 240 problems from this page produced 240 different ones, 100% — so a sheet of 20 is a new sheet almost every time.

The same skill, harder or easier

We would put this in front of a grade 4 class. That is our judgement, not a standard, and it is printed here so you can disagree with it. Everything else we put in that year.