*Use number sense or make an estimate to determine where the decimal point belongs in the product.

Question

5 x 3.4 = 17
Answer:

3.1 x 6.2 = 1922
Answer:

0.6 x 0.4 = 24
Answer:

1.8 x 1.9 = 342
Answer:

0.9 x 0.9 = 81
Answer:

Answer 1

To determine where the decimal point belongs in the products, let's analyze each multiplication:

1. 5 x 3.4:

   • Estimate: $5\times 3=15$ (approximately).
   • Actual product: $5\times 3.4=17$.
   • Answer: 17.

2. 3.1 x 6.2:

   • Estimate: $3\times 6=18$ (approximately).
   • Actual product: $3.1\times 6.2=19.22$.
   • Answer: 19.22 (not 1922).

3. 0.6 x 0.4:

   • Estimate: $0.6\times 0.4=0.24$.
   • Actual product: $0.6\times 0.4=0.24$.
   • Answer: 0.24 (not 24).

4. 1.8 x 1.9:

   • Estimate: $1.8\times 2=3.6$ (approximately).
   • Actual product: $1.8\times 1.9=3.42$.
   • Answer: 3.42 (not 342).

5. 0.9 x 0.9:

   • Estimate: $0.9\times 0.9=0.81$.
   • Actual product: $0.9\times 0.9=0.81$.
   • Answer: 0.81 (not 81).

Final Answers:

1. 17
2. 19.22
3. 0.24
4. 3.42
5. 0.81