Grade 3 math activity worksheet focusing on number sense and basic arithmetic.

Let's solve each part of the problem step by step:

---

a) Four hundred and twenty-five

- This is simply the numerical representation of "four hundred and twenty-five."
- Answer: 425

---

b) 289 _______ 291

- The missing number should be between 289 and 291.
- Answer: 290

---

c) 40 + 20 + 10 + 10 + 20 = _______

- Add all the numbers:
\[
40 + 20 + 10 + 10 + 20 = 100
\]
- Answer: 100

---

d) 175 – 25 = 150

- This equation is already solved. No further action needed.
- Answer: (No change needed)

---

e) 13 tens + 7 units = _______

- 13 tens = \( 13 \times 10 = 130 \)
- 7 units = 7
- Add them together:
\[
130 + 7 = 137
\]
- Answer: 137

---

f) 300 – 50 – 20 – 10 = _______

- Subtract step by step:
\[
300 - 50 = 250
\]
\[
250 - 20 = 230
\]
\[
230 - 10 = 220
\]
- Answer: 220

---

g) 37 + 2 = 30 + 5 + _______

- Simplify both sides:
\[
37 + 2 = 39
\]
\[
30 + 5 = 35
\]
- Let the missing number be \( x \):
\[
35 + x = 39
\]
\[
x = 39 - 35 = 4
\]
- Answer: 4

---

h) Six hundred and fifty-three

- This is the numerical representation of "six hundred and fifty-three."
- Answer: 653

---

i) 5H + _______ + _______ = 573

- Here, "5H" likely means "5 hundreds," which is 500.
- So, we need to find two numbers that add up to:
\[
573 - 500 = 73
\]
- One possible solution is splitting 73 into 70 (7 tens) and 3 (3 units).
- Answer: 70, 3 (or any other valid pair that sums to 73)

---

j) Double 84 = _______

- Double means multiplying by 2:
\[
84 \times 2 = 168
\]
- Answer: 168

---

k) 76 – 12 = 60 + _______

- Simplify the left side:
\[
76 - 12 = 64
\]
- Let the missing number be \( x \):
\[
60 + x = 64
\]
\[
x = 64 - 60 = 4
\]
- Answer: 4

---

l) 20 + 20 + 30 + 10 + 10 + 7 = _______

- Add all the numbers:
\[
20 + 20 + 30 + 10 + 10 + 7 = 97
\]
- Answer: 97

---

m) 500 + 20 + 9 = _______

- Add the numbers:
\[
500 + 20 + 9 = 529
\]
- Answer: 529

---

n) 15 Tens = _______

- 15 tens = \( 15 \times 10 = 150 \)
- Answer: 150

---

o) 5 hundreds – 3 tens = _______

- 5 hundreds = 500
- 3 tens = 30
- Subtract:
\[
500 - 30 = 470
\]
- Answer: 470

---

p) Halve 67 = _______

- Halving means dividing by 2:
\[
67 \div 2 = 33.5
\]
- Answer: 33.5

---

q) 703 = _______ + 0 + _______

- The equation can be split in many ways, but a simple solution is:
\[
703 = 700 + 0 + 3
\]
- Answer: 700, 3 (or any other valid pair that sums to 703)

---

r) 72 – 7 = 55 + _______

- Simplify the left side:
\[
72 - 7 = 65
\]
- Let the missing number be \( x \):
\[
55 + x = 65
\]
\[
x = 65 - 55 = 10
\]
- Answer: 10

---

s) 17 tens + 12 units = _______

- 17 tens = \( 17 \times 10 = 170 \)
- 12 units = 12
- Add them together:
\[
170 + 12 = 182
\]
- Answer: 182

---

Final Answers:

\[
\boxed{
\begin{array}{ll}
\text{a)} & 425 \\
\text{b)} & 290 \\
\text{c)} & 100 \\
\text{d)} & \text{(No change needed)} \\
\text{e)} & 137 \\
\text{f)} & 220 \\
\text{g)} & 4 \\
\text{h)} & 653 \\
\text{i)} & 70, 3 \\
\text{j)} & 168 \\
\text{k)} & 4 \\
\text{l)} & 97 \\
\text{m)} & 529 \\
\text{n)} & 150 \\
\text{o)} & 470 \\
\text{p)} & 33.5 \\
\text{q)} & 700, 3 \\
\text{r)} & 10 \\
\text{s)} & 182 \\
\end{array}
}
\]