Shemot 18:3–4 state:
וְאֵ֖ת שְׁנֵ֣י בָנֶ֑יהָ אֲשֶׁ֨ר שֵׁ֤ם הָֽאֶחָד֙ גֵּֽרְשֹׁ֔ם כִּ֣י אָמַ֔ר גֵּ֣ר הָיִ֔יתִי בְּאֶ֖רֶץ נָכְרִיָּֽה׃ וְשֵׁ֥ם הָֽאֶחָ֖ד אֱלִיעֶ֑זֶר כִּֽי־אֱלֹהֵ֤י אָבִי֙ בְּעֶזְרִ֔י וַיַּצִּלֵ֖נִי מֵחֶ֥רֶב פַּרְעֹֽה׃
And her two sons; of whom the name of the one was Gershom; for he said: 'I have been a stranger in a strange land'; and the name of the other was Eliezer: 'for the God of my father was my help, and delivered me from the sword of Pharaoh.'
Why tell us how many and then name them if it would just say גֵּרְשֹׁם and then אֱלִיעֶזֶר. I would already know there are two?