We have 6 rings. We skip count in 10s six times. 10, 20, 30, 40, 50, 60. Estimate = 50. Actual = 60. Each ring is 10.

There are 9 rows, with 4 groups of 10 dots in each row.
Total groups = $9 \times 4 = 36$ groups.
Actual count = $36 \times 10 = 360$ dots.

Rounding 360 to the nearest fifty gives 350.

• Estimate: $\boxed{350}$
• Actual: $\boxed{360}$

:

There are 3 columns, with 9 groups of 5 dots in each column.
Total groups = $3 \times 9 = 27$ groups.
Actual count = $27 \times 5 = 135$ dots.

Rounding 135 to the nearest ten gives 140.

• Estimate: $\boxed{140}$
• Actual: $\boxed{135}$

:

There are 4 rows and 5 columns of blocks. Each block contains $5 \times 5 = 25$ small squares.
Total blocks = $4 \times 5 = 20$ blocks.
Actual count = $20 \times 25 = 500$ squares.

Since 500 is a round number, it can also serve as the estimate.

• Estimate: $\boxed{500}$
• Actual: $\boxed{500}$

:

There are 6 rows, with 5 figures in each row.
Actual count = $6 \times 5 = 30$ figures.

Since 30 is a small, round number, the estimate can be the same.

• Estimate: $\boxed{30}$
• Actual: $\boxed{30}$