Subtraction across zero math problems with step-by-step working shown on a grid.

Let's solve each subtraction problem step by step, focusing on subtracting across zero (also known as regrouping when zeros are involved). We'll show the necessary working for each.

---

a. 600 − 246

We start from the rightmost digit (ones place).

```
600
− 246
-----
```

Step 1: Ones place
- 0 − 6 → Can't do, need to borrow.
- But the tens digit is also 0, so we need to borrow from the hundreds.

Borrow from the hundreds place:
- The 6 in the hundreds becomes 5.
- Now, we have 10 tens (from borrowing), but since we're subtracting across zero, we need to go further.

Now, take one ten from the hundreds (which was 6 → now 5), and give it to the tens place → tens become 10.
But tens are 0, so we need to break down:

→ Take 1 hundred = 10 tens → now we have 10 tens.
But we need to use one of those tens to help the ones.

So:
- Break 1 ten into 10 ones.
- But tens are 0, so first convert 1 hundred into 10 tens → now hundreds = 5, tens = 10.
- Then take 1 ten from the tens (now 9) and convert it into 10 ones → now tens = 9, ones = 10.

Now subtract:
- Ones: 10 − 6 = 4
- Tens: 9 − 4 = 5
- Hundreds: 5 − 2 = 3

✔ Answer: 354

(As shown in the image — already solved.)

---

b. 700 − 605

```
700
− 605
-----
```

Start from the ones place:

Ones:
- 0 − 5 → can't do → need to borrow.

But tens digit is 0 → need to borrow from hundreds.

Borrow from hundreds:
- Hundreds: 7 → 6
- Tens: 0 → 10 (after borrowing)
- But now, we need to borrow from tens to ones.

So:
- Tens: 10 → 9 (lend 1 ten to ones)
- Ones: 0 → 10

Now:
- Ones: 10 − 5 = 5
- Tens: 9 − 0 = 9
- Hundreds: 6 − 6 = 0

✔ Answer: 95

Wait! Let's double-check:

700 − 605 = ?

Think: 700 − 600 = 100, then 100 − 5 = 95 → ✔ Yes.

So final answer: 95

---

c. 200 − 180

```
200
− 180
-----
```

Ones: 0 − 0 = 0
Tens: 0 − 8 → can't do → borrow from hundreds.

Hundreds: 2 → 1
Tens: 0 → 10
Now, tens: 10 − 8 = 2
Hundreds: 1 − 1 = 0

So result: 20

✔ Answer: 20

---

d. 900 − 467

```
900
− 467
-----
```

Start from ones:

Ones: 0 − 7 → need to borrow.

But tens digit is 0 → borrow from hundreds.

- Hundreds: 9 → 8
- Tens: 0 → 10
- Now, borrow from tens to ones:
- Tens: 10 → 9
- Ones: 0 → 10

Now:
- Ones: 10 − 7 = 3
- Tens: 9 − 6 = 3
- Hundreds: 8 − 4 = 4

✔ Answer: 433

---

e. 300 − 140

```
300
− 140
-----
```

Ones: 0 − 0 = 0
Tens: 0 − 4 → can't do → borrow from hundreds.

- Hundreds: 3 → 2
- Tens: 0 → 10
- Now: 10 − 4 = 6
- Hundreds: 2 − 1 = 1

✔ Answer: 160

---

f. 800 − 584

```
800
− 584
-----
```

Ones: 0 − 4 → need to borrow.

Tens digit is 0 → borrow from hundreds.

- Hundreds: 8 → 7
- Tens: 0 → 10
- Now, borrow from tens to ones:
- Tens: 10 → 9
- Ones: 0 → 10

Now:
- Ones: 10 − 4 = 6
- Tens: 9 − 8 = 1
- Hundreds: 7 − 5 = 2

✔ Answer: 216

---

✔ Final Answers:

| Problem | Answer |
|--------|--------|
| a. | 354 |
| b. | 95 |
| c. | 20 |
| d. | 433 |
| e. | 160 |
| f. | 216 |

---

🔍 Summary of Key Concept: Subtracting Across Zero

When you have zeros in the minuend (top number), and you need to subtract, you must borrow through the zeros:

1. Borrow from the next non-zero digit (usually the hundreds).
2. Convert that into tens, then into ones.
3. Each zero becomes 9 after borrowing (because you "break" the higher place value).
4. Always work from right to left.

This is called regrouping across zero.

Let me know if you'd like these written out in full with arrows or diagrams!