Gardener Mr. Malina was selling strawberries. In the last nine crates, he had 28, 51, 135, 67, 123, 29, 56, 38, and 79 strawberry plants, respectively. He sold the crates whole, never removing any plants from the crates. The gardener wanted to sell the crates to three customers so that nothing was left and each of these customers had the same number of plants.

How could he do it? Provide two possibilities.

(L. Hozová)
The total number of seedlings was 606. Therefore, each of the three customers was supposed to receive 202 seedlings.

The number of seedlings in individual boxes can be divided into three groups with a sum of 202 in several ways:

$$
\begin{aligned}
& \text { a) } 135+67, \quad 123+79, \quad 56+51+38+29+28 \text {, } \\
& \text { b) } 135+38+29, \quad 123+51+28, \quad 79+67+56 \text {, } \\
& \text { c) } \quad 135+38+29, \quad 123+79, \quad 67+56+51+28 \text {, } \\
& \text { d) } 135+67, \quad 123+51+28, \quad 79+56+38+29 \text {. }
\end{aligned}
$$

These divisions correspond to the possible ways the gardener could have sold his boxes.

Evaluation. 2 points for the total sum and the discovery that each was supposed to receive 202 seedlings; 2 points for each of the two correct divisions.

Notes. When manually testing the possibilities, it is advisable to start with the larger numbers.

The given numbers can be divided into three groups with the same sum without having to determine the total sum in advance. Consider this insight when evaluating.

In each of the cases mentioned, it is possible to consider six possible assignments of the three groups of boxes to the three customers. Solutions based on this idea should also be considered correct.