Let’s solve each multiplication problem one by one. I’ll multiply the top number by the bottom number for each pair.
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First row:
1.
21 × 21
→ 21 × 20 = 420
→ 21 × 1 = 21
→ 420 + 21 =
441
2.
41 × 22
→ 41 × 20 = 820
→ 41 × 2 = 82
→ 820 + 82 =
902
3.
33 × 10
→ Just add a zero:
330
4.
71 × 11
→ 71 × 10 = 710
→ 71 × 1 = 71
→ 710 + 71 =
781
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Second row:
5.
80 × 10
→ Add a zero:
800
6.
54 × 12
→ 54 × 10 = 540
→ 54 × 2 = 108
→ 540 + 108 =
648
7.
43 × 20
→ 43 × 2 = 86, then add a zero:
860
8.
63 × 12
→ 63 × 10 = 630
→ 63 × 2 = 126
→ 630 + 126 =
756
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Third row:
9.
44 × 22
→ 44 × 20 = 880
→ 44 × 2 = 88
→ 880 + 88 =
968
10.
30 × 21
→ 30 × 20 = 600
→ 30 × 1 = 30
→ 600 + 30 =
630
11.
31 × 66
→ Let’s break it: 31 × 60 = 1860; 31 × 6 = 186
→ 1860 + 186 =
2046
12.
51 × 18
→ 51 × 10 = 510
→ 51 × 8 = 408
→ 510 + 408 =
918
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Fourth row:
13.
24 × 12
→ 24 × 10 = 240
→ 24 × 2 = 48
→ 240 + 48 =
288
14.
45 × 11
→ 45 × 10 = 450
→ 45 × 1 = 45
→ 450 + 45 =
495
15.
90 × 10
→ Add a zero:
900
16.
54 × 32
→ 54 × 30 = 1620
→ 54 × 2 = 108
→ 1620 + 108 =
1728
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Final Answer:
441, 902, 330, 781, 800, 648, 860, 756, 968, 630, 2046, 918, 288, 495, 900, 1728
Parent Tip: Review the logic above to help your child master the concept of double digit multiplication worksheets pdf.
