About this preparation
Хочу зробити діагностичний тест з математики для учня Velvet Adewale, 3 клас, на 55 хвилин, середньої складності. Потрібно зосередитися на column subtraction.
Reid Rachel
Preparation author
Diagnostic tasks
Below is the full list of tasks with correct answers and explanations. In a lesson the tutor can hide the answers and reveal them after the student tries.
1
What is 64 - 27?
37
47
57
33
Explanation: Subtract the ones first: 4 - 7 needs regrouping, so 64 becomes 5 tens and 14 ones. Then 14 - 7 = 7 and 5 - 2 = 3. The answer is 37.
2
What is 83 - 46?
27
37
47
57
Explanation: Regroup 83 as 7 tens and 13 ones. Then 13 - 6 = 7 and 7 - 4 = 3. The answer is 37.
3
What is 152 - 38?
124
114
104
134
Explanation: Regroup 152 as 1 hundred, 4 tens, and 12 ones. Then 12 - 8 = 4, 4 - 3 = 1, and 1 hundred stays. The answer is 114.
4
What is 301 - 159?
152
142
132
242
Explanation: Regroup carefully across the zeros: 301 becomes 2 hundreds, 9 tens, and 11 ones. Then 11 - 9 = 2, 9 - 5 = 4, and 2 - 1 = 1. The answer is 142.
5
What is 425 - 178?
257
247
267
357
Explanation: Regroup 425 as 3 hundreds, 11 tens, and 15 ones. Then 15 - 8 = 7, 11 - 7 = 4, and 3 - 1 = 2. The answer is 247.
6
Which subtraction is correct?
72 - 35 = 47
72 - 35 = 37
72 - 35 = 27
72 - 35 = 57
Explanation: Since 12 - 5 = 7 and 6 - 3 = 3 after regrouping, the correct result is 37.
7
Which of these subtraction problems need regrouping?
52 - 18
74 - 21
63 - 47
90 - 34
Explanation: Regrouping is needed when the ones digit in the top number is smaller than the ones digit being subtracted. That happens in 52 - 18, 63 - 47, and 90 - 34.
8
What is 600 - 275?
335
325
315
425
Explanation: Regroup 600 as 5 hundreds, 9 tens, and 10 ones. Then 10 - 5 = 5, 9 - 7 = 2, and 5 - 2 = 3. The answer is 325.
9
A library had 248 books. It gave away 96 books. How many books are left?
152
162
172
142
Explanation: Subtract 248 - 96. Regroup 248 as 1 hundred, 14 tens, and 8 ones. Then 8 - 6 = 2, 14 - 9 = 5, and 1 - 0 = 1. The answer is 152? Wait, check carefully: 248 - 96 = 152. So the correct answer is 152.
10
What number should go in the box? 7□ - 28 = 45
1
2
3
4
Explanation: The missing number makes 73 - 28 = 45. So the box must be 3.
