【Answer】Solution: "Each put in" should mean the number of each type put in is equal,
since the sum of the area of each small square and a triangle is $2 \times 2 + 3 \times 3 \div 4 = 6.25$,
the area of the large square is $7 \times 7 = 49$,
and $49 \div 6.25 = 7.84$,
so the maximum number that can be put in is 7 each,
the following diagram shows it can be done,
5. (10 points) Lelé placed some small squares and isosceles right triangles without overlapping on the bottom of a large square box with a side length of 7 cm. If the side lengths of the small squares are all 2 cm, and the hypotenuse lengths of the isosceles right triangles are all 3 cm, then the maximum number of each shape he can place is $\qquad$.