Number.—The farm problem also supplies abundant opportunity for gaining experience with number. In addition to the actual measurement of the materials used for fences and buildings, the scope may be widened, where conditions warrant, to include estimates and calculations of the amount of the material used.
For example, how many inches or feet of wire will be needed to make a three-wire fence of given length? How large a piece of cardboard will be needed to cut boards one fourth or one half inch wide for a four-board fence fifteen inches long?
These estimates may be translated, as far as the children are able to appreciate the connection, into quantities and values of the same material in real problems connected with real farms. It is important, however, to be careful not to carry work of this sort so far beyond the experience of the children that it becomes wholly foreign and abstract to them. We are too apt to forget that it is experience and not objects, which is the vital factor in concreteness.
Fig. 44.—Robinson Crusoe. Third grade. Columbia, Missouri.
In connection with the nature study a variety of number exercises grow out of the questions which the situation prompts. As, for example, in connection with the corn crop: How many seeds were planted? In how many rows? How many seeds in a row? How many came up? How many failed to germinate? How many more came up than failed? If each good seed should produce two ears of corn, how many would we have? What would they be worth at a given price? etc.
Fig. 45.—Pueblo Indian village. Second grade. Columbia, Missouri.