Multiplying by Multiples of 10 - Free Printable

Let's solve the multiplication problems on "Multiplying by 10s & 100s Sheet 2" step by step.

The key idea here is to use your basic multiplication facts and then adjust for zeros. For example:

- If you know that $3 \times 7 = 21$, then:
- $30 \times 7 = 210$ (add one zero)
- $300 \times 7 = 2100$ (add two zeros)
- $30 \times 70 = 2100$ (add one zero to each number → total two zeros)

We'll apply this rule to all problems.

---

✔ Answers with Explanations:

#### Left Column (1–20):

1) $300 \times 4 = 1200$
→ $3 \times 4 = 12$, add two zeros → $1200$

2) $3 \times 50 = 150$
→ $3 \times 5 = 15$, add one zero → $150$

3) $40 \times 5 = 200$
→ $4 \times 5 = 20$, add one zero → $200$

4) $2 \times 80 = 160$
→ $2 \times 8 = 16$, add one zero → $160$

5) $60 \times 40 = 2400$
→ $6 \times 4 = 24$, add two zeros → $2400$

6) $80 \times 5 = 400$
→ $8 \times 5 = 40$, add one zero → $400$

7) $4 \times 300 = 1200$
→ $4 \times 3 = 12$, add two zeros → $1200$

8) $60 \times 20 = 1200$
→ $6 \times 2 = 12$, add two zeros → $1200$

9) $50 \times 60 = 3000$
→ $5 \times 6 = 30$, add two zeros → $3000$

10) $4 \times 500 = 2000$
→ $4 \times 5 = 20$, add two zeros → $2000$

11) $80 \times 3 = 240$
→ $8 \times 3 = 24$, add one zero → $240$

12) $20 \times 90 = 1800$
→ $2 \times 9 = 18$, add two zeros → $1800$

13) $40 \times 20 = 800$
→ $4 \times 2 = 8$, add two zeros → $800$

14) $70 \times 30 = 2100$
→ $7 \times 3 = 21$, add two zeros → $2100$

15) $900 \times 4 = 3600$
→ $9 \times 4 = 36$, add two zeros → $3600$

16) $6 \times 500 = 3000$
→ $6 \times 5 = 30$, add two zeros → $3000$

17) $60 \times 7 = 420$
→ $6 \times 7 = 42$, add one zero → $420$

18) $7 \times 300 = 2100$
→ $7 \times 3 = 21$, add two zeros → $2100$

19) $70 \times 60 = 4200$
→ $7 \times 6 = 42$, add two zeros → $4200$

20) $50 \times 9 = 450$
→ $5 \times 9 = 45$, add one zero → $450$

---

#### Right Column (21–40):

21) $80 \times 5 = 400$
→ $8 \times 5 = 40$, add one zero → $400$

22) $60 \times 9 = 540$
→ $6 \times 9 = 54$, add one zero → $540$

23) $8 \times 700 = 5600$
→ $8 \times 7 = 56$, add two zeros → $5600$

24) $10 \times 80 = 800$
→ $1 \times 8 = 8$, add two zeros → $800$

25) $60 \times 80 = 4800$
→ $6 \times 8 = 48$, add two zeros → $4800$

26) $9 \times 90 = 810$
→ $9 \times 9 = 81$, add one zero → $810$

27) $7 \times 500 = 3500$
→ $7 \times 5 = 35$, add two zeros → $3500$

28) $80 \times 90 = 7200$
→ $8 \times 9 = 72$, add two zeros → $7200$

29) $40 \times 70 = 2800$
→ $4 \times 7 = 28$, add two zeros → $2800$

30) $7 \times 50 = 350$
→ $7 \times 5 = 35$, add one zero → $350$

31) $60 \times 80 = 4800$
→ $6 \times 8 = 48$, add two zeros → $4800$

32) $9 \times 70 = 630$
→ $9 \times 7 = 63$, add one zero → $630$

33) $500 \times 7 = 3500$
→ $5 \times 7 = 35$, add two zeros → $3500$

34) $7 \times 90 = 630$
→ $7 \times 9 = 63$, add one zero → $630$

35) $40 \times 80 = 3200$
→ $4 \times 8 = 32$, add two zeros → $3200$

36) $70 \times 6 = 420$
→ $7 \times 6 = 42$, add one zero → $420$

37) $30 \times 80 = 2400$
→ $3 \times 8 = 24$, add two zeros → $2400$

38) $50 \times 7 = 350$
→ $5 \times 7 = 35$, add one zero → $350$

39) $80 \times 80 = 6400$
→ $8 \times 8 = 64$, add two zeros → $6400$

40) $8 \times 60 = 480$
→ $8 \times 6 = 48$, add one zero → $480$

---

✔ Final Answer Key:

| # | Problem | Answer |
|---|----------------|--------|
| 1 | 300 × 4 | 1200 |
| 2 | 3 × 50 | 150 |
| 3 | 40 × 5 | 200 |
| 4 | 2 × 80 | 160 |
| 5 | 60 × 40 | 2400 |
| 6 | 80 × 5 | 400 |
| 7 | 4 × 300 | 1200 |
| 8 | 60 × 20 | 1200 |
| 9 | 50 × 60 | 3000 |
|10 | 4 × 500 | 2000 |
|11 | 80 × 3 | 240 |
|12 | 20 × 90 | 1800 |
|13 | 40 × 20 | 800 |
|14 | 70 × 30 | 2100 |
|15 | 900 × 4 | 3600 |
|16 | 6 × 500 | 3000 |
|17 | 60 × 7 | 420 |
|18 | 7 × 300 | 2100 |
|19 | 70 × 60 | 4200 |
|20 | 50 × 9 | 450 |
|21 | 80 × 5 | 400 |
|22 | 60 × 9 | 540 |
|23 | 8 × 700 | 5600 |
|24 | 10 × 80 | 800 |
|25 | 60 × 80 | 4800 |
|26 | 9 × 90 | 810 |
|27 | 7 × 500 | 3500 |
|28 | 80 × 90 | 7200 |
|29 | 40 × 70 | 2800 |
|30 | 7 × 50 | 350 |
|31 | 60 × 80 | 4800 |
|32 | 9 × 70 | 630 |
|33 | 500 × 7 | 3500 |
|34 | 7 × 90 | 630 |
|35 | 40 × 80 | 3200 |
|36 | 70 × 6 | 420 |
|37 | 30 × 80 | 2400 |
|38 | 50 × 7 | 350 |
|39 | 80 × 80 | 6400 |
|40 | 8 × 60 | 480 |

---

✔ Tip: Always break down the numbers: remove the zeros, multiply the base numbers, then add back the zeros.

For example:
$70 \times 60 = (7 \times 6) \times 100 = 42 \times 100 = 4200$

This method makes multiplying large numbers easy!

Let me know if you'd like a printable version or help with any specific problem!