Missing addend with 2-digit numbers

Difficulty Starter · Set q5s0ba

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1
34+=43
2
77+=86
3
39+=47
4
74+=81
5
85+=91
6
53+=62
7
66+=74
8
99+=103
9
85+=90
10
97+=105
11
47+=56
12
59+=67
13
32+=40
14
28+=35
15
19+=22
16
28+=31
17
48+=51
18
16+=25
19
39+=46
20
58+=60

What is in this set

The numbers in this set run from 12 to 107.
Every problem in it will need a borrow from the column to the left.
A careful solution takes 2 written steps on average.
The mistake this set invites most often, in 100% of the problems: the two numbers on the page were added — a missing part is found by taking one away from the total, not by adding.
Answers are a whole number.

Drawing 240 problems from this page produced 176 different ones, 73% — 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 3 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.