**10 is even, it can be paired** All the tens and hundreds can be paired. * **10**: Represented by a single block rod of 1010 units, split with arrows into two equal groups of 55 unit cubes each (5+5=105 + 5 = 10). * **20**: Represented by two block rods of 1010 units, split with arrows into two equal groups, each containing one block rod of 1010 units (10+10=2010 + 10 = 20). * **50**: Represented by five block rods of 1010 units, split with arrows into two equal groups, each containing two block rods of 1010 units and 55 unit cubes (25+25=5025 + 25 = 50).

Answer: Since 10=2×510 = 2 \times 5, 1010 is an even number. Consequently, any multiple of 1010 (such as 20=2×1020 = 2 \times 10, 50=2×2550 = 2 \times 25, or any hundred) can always be partitioned into two equal groups with no remainder.

Step-by-step solution

Step 1: Understand pairing and even numbers

A whole number is called even if it can be divided into 22 equal groups without leaving any remainder. Here, 1010 items can be split into 22 equal groups of 55, which shows that 1010 is an even number.

Step 2: Analyze the decomposition of 10

A rod representing 11 ten consists of 1010 individual unit cubes. When divided equally between 22 groups, each group gets exactly 55 unit cubes, leaving no remainder.

Step 3: Analyze the decomposition of 20

The number 2020 consists of 22 rods of ten. We can divide the rods directly so that each group receives 11 full rod of 1010 units, giving 10+10=2010 + 10 = 20.

Step 4: Analyze the decomposition of 50 and general tens

The number 5050 consists of 55 rods of ten. Four rods split evenly into 22 rods for each group, and the remaining rod of 1010 splits into two groups of 55 units. Thus, each group receives 22 rods and 55 units, totaling 25+25=5025 + 25 = 50. In general, any multiple of 1010 can be written as 10k=2(5k)10k = 2(5k), so all multiples of 1010 and 100100 are always even and can be paired.

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